What Challengers Operators will Face when Digital Home is Befalling

The growth of internet-enabled devices and a maturing of networking technologies indicate the digital home is entering a new phase. But while operators believe the home offers important new service and revenue opportunities, considerable challenges remain. Operators are thus proceeding cautiously.
Here is a look at the status of the digital home in terms of:

• Services driving home networking
• Wireless and wireline homenetworking technologies
• Challenges

Services driving home networking

IPTV and video delivery are key services that place significant demands on the home network in terms of bandwidth and reach. Typically the residential gateway that links the home to the broadband network, and the set-top box where video is consumed are located apart. Connecting the two has been a challenge for telcos. In contrast, cable operators (MSOs) have always networked video around the home. The MSOs’ challenge is adding voice and linking home devices such as PCs.
Now the telcos are meeting the next challenge: distributing video between multiple set-tops and screens in the home.
Other revenue-generating home services interesting service providers include:

• A contract to support a subscriber’s home network
• E-health: remote monitoring a patient’s health
• Home security using video cameras
• Media content: enabling a user to grab home-stored content when on the move
• Smart meters and energy management

One development that operators cannot ignore is ‘over-the-top’ services. Users can get video from third parties directly over the internet. Such over-the-top services are a source of competition for operators and complicate home networking requirements in that users can buy and connect their own media players and internet-enabled TVs. Yet any connectivity issues and it is the operator that will get the service call.
However, over-the-top services are also an opportunity in that they can be integrated as part of the operator’s own offerings and delivered with quality of service (QoS).
 
Wireless and wireline home networking technologies

Operators face a daunting choice of networking technologies. Moreover, no one technology promises complete, reliable home coverage due to wireless signal fades or wiring that is not where it is needed.
As a result operators must use more than one networking technology.  Within wireline there are over half a dozen technology options available. And even for a particular wireline technology, power line for example, operators have multiple choices.
Wireless

• Wi-Fi is the technology of choice with residential gateway vendors now supporting the IEEE 802.11n standard which extends the data rate to beyond 100 megabits-per-second (Mbps). An example is Orange’s Livebox2 home gateway, launched in June 2009.

• The second wireless option is femtocells, that is now part of the define features of the Home Gateway Initiative’s next-generation (Release 3) platform, planned for 2010.  Mass deployment of femtocells is still to happen and will only serve handsets and consumer devices that are 3G-enabled.

Wireline

• If new wiring of a home is possible, operators can use Ethernet Category-5 cabling, or plastic optical fibre (POF) which is flexible and thin.

• More commonly existing home wiring like coaxial cable, electrical wiring (powerline) or telephone wiring is used. Operators have adopted HomePNA which supports phone wiring; the Multimedia over Coax Alliance (MoCA) that uses coaxial cabling; and the HomePlug Powerline Alliance’s HomePlug AV, a powerline technology that uses a home’s power wiring over which data is transmitted.

• Gigabit home networking (G.hn) is a new standard being developed by the International Telecommunication Union. Set to appear in products in 2010, the standard can work over three wireline media: phone, coax and powerline. AT&T, BT and NTT are backing G.hn though analysts question its likely impact overall.  Indeed one operator says the emerging standard could further fragment the market.

 
Challenges

• Building a home network is complex due to the many technologies and protocols involved.

• Users have an expectation that operators will solve their networking issues yet operators only own and are interested in their own home equipment: the gateway and set-top box. Operators risk getting calls from frustrated users that have deployed a variety of consumer devices.  Such calls impact the operators’ bottom line.

• Effective tools and protocols for home networking monitoring and management is a must for the operators. The Broadband Forum’s TR-069 and the Universal Plug and Play (UPnP) diagnostic and QoS software protocols continue to evolve but so far only a fraction of their potential is being used.

Operators understandably are proceeding with care as they cross the home's front door to ensure their offerings are simple and reliable. Otherwise any revenue-potential home networking promises as well as a long-term relationship with the subscriber will be lost.

Forecast on China and Global PON Market

China has become the world's biggest market for passive optical network (PON) technology even though deployments there have barely begun. That is because China, with approximately a quarter of a billion households, dwarfs all other markets. Yet according to market research firm Ovum, only 7% of Chinese homes were connected by year end 2011.

 

Until recently Japan and South Korea were the dominant markets. And while PON deployments continue in these two markets, the rate of deployments has slowed as these optical access markets mature. 

 

Slightly more than 4 million PON optical line terminals (OLTs) ports, located in the central office, were shipped in Asia Pacific in 2011, of which China accounted for the majority. Worldwide OLT shipments for the same period totaled close to 4.5 million. The fact that in China the ratio of OLT to optical network terminal (ONT), the end terminal at the home or building, deployed is relatively low highlights that in the Chinese market the significant growth in PON end terminals is still to come.

The strength of the Chinese market has helped local system vendors Huawei, ZTE and Fiberhome become leading global PON players, accounting for over 85% of the OLTs sold globally in 2012, says Julie Kunstler, principal analayst, optical components at Ovum. Moreover, around 60% of fibre-to-the-x deployments in Europe, Middle East and Africa were supplied by the Chinese vendors. The strongest non-Chinese vendor is Alcatel-Lucent.

Ovum says that the State Grid China Corporation, the largest electric utility company in China, has begun to deploy EPON for their smart grid trial deployments. PON is preferred to wireless technology because of its perceived ability to secure the data. This raises the prospect of two separate PON lines going to each home. But it remains to be seen, says Kunstler, whether this happens or whether the telcos and utilities share the access network.

"After China the next region that will have meaningful numbers is Eastern Europe, followed by South and Central America and we have already seen it in places like Russia,” says Kunstler. Indeed FTTx deployments in Eastern Europe already exceed those in Western Europe.

 

EPON and GPON

In China both Ethernet PON(EPON) and Gigabit PON (GPON) are being deployed. Ovum estimates that in 2011, 65% of equipment shipments were EPON while GPON represented 35% GPON in China.

China Telecom was the first of the large operators in China to deploy PON and began with EPON.  Ovum is now seeing deployments of GPON and in the 3rd quarter of 2012, GPON OLT deployments have overtaken EPON. 

China Mobile, not a landline operator, started deployments later and chose GPON. But these GPON deployments are on top of EPON, says Kunstler: "EPON is still heavily deployed by China Telecom, while China Mobile is doing GPON but it is a much smaller player." Moreover, Chinese PON vendors also supplying OLTs that support EPON and GPON, allowing local decisions to be made as to which PON technology is used.

One trend that is impacting the traditional PON optical transceiver market is the growing use of board-based PON optical sub-assemblies (BOSAs). Such PON optics dispenses with the traditional traditional optical module form factor in the interest of trimming costs.

“A number of the larger, established ODMs [original design manufacturers] have begun to ship BOSA-based PON CPEs,” says Kunstler.

10 Gigabit PON

Ovum says that there has been very few deployments of next generation 10G EPON and XG-PON, the 10 Gigabit version of GPON. 

"There have been small amounts of 10G [EPON] in China," says Kunstler. "We are talking hundreds or thousands, not the tens of thousands [of units]."

One reason for this is the relative high cost of 10 Gigabit PON which is still in its infancy. Another is the growing shift to deploy fibre-to-the-home (FTTh) versus fibre-to-the-building deployments in China. 10 Gigabit PON makes more sense in multi-dwelling units where the incoming signal is split between apartments. Moving to 10G EPON boosts the incoming bandwidth by 10x while XG-PON would increase the bandwidth by 4x.  "The need for 10 Gig for multi-dwelling units is not as strong as originally thought," says Kunstler. 

 

It is a chicken-and-egg issue with 10G PON, says Kunstler.  The price of 10G optics would go down if there was more demand, and if there was more demand, the optical vendors would work on bringing down cost. "10G GPON will happen but will take longer," says Kunstler, with volumes starting to ramp from 2014.

However, Ovum thinks that a stronger market application for 10G PON will be for supporting wireless backhaul. The market research company is seeing early deployments of PON for wireless backhaul especially for small cell sites (e.g. picocells). Small cells are typically deployed in urban areas which is where FTTx is deployed. It is too early to know the market forecast for this application but PON will join the list of communications technologies supporting wireless backhaul.

 

Challenges

Despite the huge expected growth in deployments, driven by China, challenges remain for PON optical transceiver and chip vendors.

The margins on optics and PON silicon continue to be squeezed. ODMs using BOSAs are putting pricing pressure on PON transceiver costs while the vertical integration strategy of system vendors such as Huawei, which also develops some of its own components squeezes, out various independent players. Huawei has its own silicon arm called HiSilicon and its activities in PONhas impacted the chip opportunity of the PON merchant suppliers.  

"Depending upon who the customer is, depending upon the pricing, depending on the features and the functions, Huawei will make the decision whether they are using HiSilicon or whether they are using merchant silicon from an independent vendor, for example," says Kunstler.

 

There has been consolidation in the PON chip space as well as several new players. For example, Broadcom acquired Teknouvs and Broadlight while Atheros acquired Opulan and Atheros was then acquired by Qualcomm. Marvell acquired a very small start-up and is now competing with Atheros and Broadcom.

 

 

See more products on Passive Optical modules from the website http://www.optoroute.com.cn/

CFP2 Pluggable Module Gains Industry Momentum

Finisar and Oclaro unveiled their first CFP2 optical transceiver products at the recent ECOC exhibition in Amsterdam. JDSU also announced that its ONT-100G test equipment now supports the latest 100Gbps module form factor. So do you know the feature of  CFP2 optical transceivers?

 

The CFP2 is the follow-on module to the CFP, supporting the IEEE 100 Gigabit Ethernet and ITU OTU4 standards. It is half the size of the CFP (see image) and typically consumes half the power. Equipment makers can increase the front-panel port density from four to eight by migrating to the CFP2.

 

Oclaro also announced a second-generation CFP supporting the 100GBASE-LR4 10km and OTU4 standards that reduces the power consumption from 24W to 16W. The power saving is achieved by replacing a two-chip silicon-germanium 'gearbox' IC with a single CMOS chip. The gearbox translates between the 10x10Gbps electrical interface and the 4x25Gbps signals interfacing to the optics. 

 

The CFP2, in contrast, doesn’t include the gearbox IC.

"One of the advantages of the CFP2 module is we have a 4x25Gbps electrical interface," says Rafik Ward, vice president of marketing at Finisar. "That means that within the CFP2 module we can operate without the gearbox chip." The result is a compact, lower-power design, which is further improved by the use of optical integration. 

 

 

The transmission part of the CFP module typically comprises four externally modulated lasers (EMLs), each individually cooled. The four transmitter optical sub-assemblies (TOSAs) then interface to a four-channel optical multiplexer. 

Finisar's CFP2 design uses a single TOSA holding four distributed feedback (DFB) lasers, a shared thermo-electric cooler and the multiplexer. The result of using DFBs and an integrated TOSA is that Finisar's CFP2 consumes just 8W.

Oclaro uses photonic integration on the receiver side, integrating four receiver optical sub-assemblies (ROSAs) as well as the optical demultiplexer into a single design, resulting in a 12W CFP2. 

 

 

The standards-based client-side interfaces is an attractive market for test and measurement companies. For line-side optical transmission, much of the development work is proprietary such that developing a test set to serve vendors' proprietary solutions is not feasible.

The biggest engineering challenge for the CFP2 is its adoption of high-speed 25Gbps electrical interfaces. "The CFP was based on third generation, mature 10 Gig I/O [input/output]," says Brooks. "To get to cost-effective CFP2 [modules] is a very big jump: that 2.5x faster [interface] equates to about a 6x greater difficulty in signal integrity issues, microwave techniques etc." 

The company says that what has been holding up the emergence of the CFP2 module has been the 104-pin connector: "The pluggable connector is the big headache," says Brooks. "The expectation is that very soon we should get some early connectors."

The test equipment also supports developers of the higher-density CFP4 module, and other form factors such as the QSFP2.

 

 

At ECOC, Oclaro demonstrated interoperability between its latest CFP and the CFP2. “It shows that the new modules will talk to existing ones,” says Robert Blum, director of product marketing for Oclaro's photonic components.

Meanwhile JDSU demonstrated its ONT-100G test set that supports the CFP2 and CFP4 MSAs.

"Initially the [test set] applications are focused on those doing the fundamental building blocks [for the 100G CFP2] – chip vendors, optical module vendors, printed circuit board developers," says Paul Brooks, director for JDSU's high speed transport test portfolio. "We will roll out more applications within the year that cover early deployment and production."

 

 

 For more information on CFP products, please visit http://www.optoroute.com.cn/

Is it Real or just Fantacy: Optical Transceivers Market will Soar 50% by 2017?

Recently, Analyst  Vladimir Kozlov forcast that the price declines in 2012 were brutal but they will not happen again during the forecast period, here are some details:

• The optical transceiver market will grow to US $5.1bn in 2017
• The fierce price declines of 2012 will lessen during the forecast period
• Stronger traffic growth could have a significant positive effect on transceiver market growth

The global optical transceiver market will grow strongly over the next five year to $5.1bn in 2017, from $3.4bn in 2012. So claims market research company.

"That [market value] does not include tunable lasers, wavelength-selective switches, pump lasers and amplifiers which will add some $1bn or $2bn more in 2017," says Vladimir Kozlov.

One key assumption underpinning the forecast is that competitive pressures will ease. "The price declines in 2012 were brutal but they will not happen again [during the forecast period]," says Kozlov.


Optical Transceivers

The optical transceiver market saw price declines as high as 30 percent last year. These were not new products ramping in volume where sharp price declines are to be expected, says Kozlov.  Last year also saw fierce competition among the service providers while the steepest price declines were experienced by the telecom equipment makers.

One optical transceiver sector that performed well last year is high-speed optical transceivers and in particular Ethernet.

The 100 Gigabit Ethernet (GbE) market saw revenue growth due to strong demand for the 100GBASE-LR4 10km transceiver even though its unit price declined 30 percent. This is a sector the Chinese optical transceiver players are eyeing as they look to broaden the markets they address.

One unheralded market that did well was 40 Gigabit transceivers for telecoms and the data centre. "This is 40 Gig short reach mostly - up to 100m - but also 10km reach transceivers did well in the data centre," says Kozlov.

LightCounting expects the steady growth of 40GbE to continue; 40GbE transceivers use 10 Gig technology co-packaged into one module, offer improved port density and have a lower power and cost compared to four 10GbE transceivers.

Even the veteran 10GbE market continues to grow. Some 7-8M 10GbE short reach and long reach units were sold in 2012 growing to 10M units this year.

Meanwhile, the 100 Gigabit coherent long-haul transponder market was small in 2012. The optical vendors only started selling in volume last year and most of the system vendors manufacture their own 100 Gigabit-per-second (Gbps) designs using discrete components. "Those companies that sell modulators and receivers for 100 Gig did really well in 2012," says Kozlov.

It is expected that the 100Gbps coherent transponder market will grow in 2013 as system vendors embrace more third-party 100 Gig transponders. "We estimate that the optical transceiver vendors captured 10-15 percent of the 40 and 100 Gig market and this will grow to 18-20 percent in 2013," says Kozlov.

Other markets that grew in 2012 include optical access. The fibre-to-the-x (FTTx) continues to grow in terms of units shipped, with transceivers and board optical sub-assembly (BOSA) designs sharing the volumes.

Kozlov says that the number of optical network units (ONU) exceeded by more than double the number of FTTx subscribers added in 2012: 35-40M ONU transceivers and BOSAs compared to 15M new subscribers.

The result was a market value of $700M in 2012 compared to $300M in 2009. But because of the excess in shipments compared to new subscribers, Kozlov expects the FTTx market to slow down. "That is probably a sure sign that it is going to grow again," he quips.

 
Market Expectations

Kozlov will be watching how the optical interconnect market does this year. The active optical cable market did well in 2012 and this is likely to continue. Kozlov is interested to see if silicon photonics starts to make its mark in the transceiver market, citing as an example Cisco's in-house silicon photonics-based CPAK transceiver. He also expects the 40G and 100Gbps module makers to do well.

Kozlov stresses the wide discrepancy between video traffic growth through 2017 as forecast by Bell Labs and by Cisco Systems. This is important because the optical transceiver forecast model  is sensitive to traffic growth. LightCounting has averaged the two forecasts but if video traffic grows more quickly, the overall transceiver market will exceed the market research company's 2017 forecast.

Another reason why Kozlov is upbeat about the market's prospects is that while the system vendors suffered the sharpest price declines - up to 35 percent in 2012 - this will not continue.

The sharp falls in equipment prices were due largely to the fierce competition provided by the Chinese giants Huawei and ZTE. But relief is expected with government initiatives in Europe and the United States to limit the influence of Huawei and ZTE, says Kozlov.

The U.S. government has effectively restricted sales of Huawei and ZTE networking equipment to major U.S. carriers due to cyber security concerns, while the European Commission has determined that Huawei and ZTE are both inflicting damage on European equipment vendors by dumping products onto the European market.


For more information on optical products, please feel free to visit http://www.optoroute.com.cn/  

How to classify FTTX Topology

FTTX technology is referred to access network technology which generally divided into point-to-point (P2P) and point-to-multipoint (P2MP) two kinds of access methods,.  A passive optical network (PON) is a point-to-multipoint network architecture

FTTX can be FTTH (fiber to the home), FTTE (Fiber to the telecom enclosure), FTTC (Fiber to the curb), the FTTB / O (optical fiber to the building / office) and so on.

FTTX Topology Classification

P2P (point-to-point)

The point-to-point (P2P) architecture has a core switch at the central office, which connects over optical fiber cables to an aggregation switch at the distribution points. These locations are typically your street corners, etc. The aggregation switches have many fiber ports and each port will directly connect to an ONT (Optical Network Termination) placed at the residential localities using fiber cables.

P2M (point-to-multi-point):

The point-to-multi-point (P2M)/ passive optical network (PON) architecture is the same, except in the distribution points. Instead of the active switches with fiber ports, passive splitters are used. These splitters do not require any power supply and they can divide an optical signal into 32, 64 or even 128 shared connections. The same signal is transmitted to all the houses beyond the splitter, but each ONT in each house knows how to decipher the information meant only for itself. Of course, the ONTs used in P2P are different from the ones used in P2M. Also, the total bandwidth is shared between all these shared connections.

Comparison of both topologies

	Ethernet	PON
Scalability	100 Mbit/s to 10 Gbit/s	2.5 to 10Gbit/s
Bitrate sharing	Dedicated bitrate	shared bitrate
Security	High through dedicated medium	Requires encryption, vulnerable to DoS attacks
Upstream traffic management	Highly sophisticated through switch matrix	Limited by capabilities of MAC protocol
Interoperability OLT-CPE	Easy because of ubiquitous technology	Still challenging
Per-subscriber CO power consumption	We defined low value (≈2W), independent of take rate	Depends on take rate - from very high to very low
≈1150 homes connected per pack	Depends on take rate - from very high to very low

How can you determine the best topology?

You need to understand your options for your deployment of fiber in a variety of topologies.

• Which business designenterprize model are you planning to apply today?
• Which business designenterprize model are you planning to apply in Two decades from now?
• Are limitations for your deployment of certain topologies with different serious research into the existing infrastructure (e.g., ductwork), or conservative presumptions?

Just in case your access infrastructure must be flexible, business designenterprize model and technology-agnostic, then deploy a place-to-point fiber.

How will you determine the very best access technology?

• Understand your choices for the technologies to be used inside the fiber topology.
• Which peak bitrates will clientsyour site site visitors require inside the time period of we've got we have got we've got the technology (e.g., 5 years) that you just deploy today?
• Do you want to differentiate technologies between low-tier and-tier residentials, SMEs, companies?
• Can be a unified approach simpler and cheaper ultimatelyultimately?
• Would you like an Radiation video overlay?

Just in case your technology choice should be equally suitable for an array of clients, be highly scalable, mature, secure, then deploy Ethernet.


For more information on FTTX, please visit http://www.optoroute.com.cn/

How to Design and Install Cabling System in Campus

With the spread of computer applications, along with the rapid development of network technology, the campus network has become an essential school information infrastructure. The implementation of the campus network, for schools to adapt to new developments and make fuller use of existing teaching resources for teching, management has provided a guarantee. Construction of intelligent building network as the physical basis. Using a variety of transmission media of the communication management device and the terminal connected. Its performance can affect the normal operation of the network and the length of life. Therefore, the design of a scientific and rational, optimized campus cabling system is to further play a variety of network equipment functions, the information and communication technologies to achieve the school a good development, improve the level of application management key. 

 

The Campus Cabling System Overview

 

According to GB/T 50314 "Intelligent Building Design Standards" about the demarcation of ten categories of building regulations, school buildings, including ordinary full-time colleges and universities, high schools and senior vocational schools, junior and primary schools, nurseries and kindergartens school buildings, etc. Different levels of the school, its size, environment, personnel are different, so the campus cabling system requirements will be different. 

 

The Campus Cabling System Features

 

In China, a full time ordinary institutions of higher learning, the campus area (not including campuses district), in general, nearly acres, some even a few acres. Distribution of number of buildings on campus and many species has a teaching building, comprehensive building, laboratory buildings, art building (including the campus theater, dance halls on campus, campus cultural centers), libraries, teachers' apartments, student apartments, gymnasium, conference centers, schools' hospitals, canteens and so on. Their application also includes teaching, testing, physical, network, accommodation, living, health care and other aspects. For colleges and universities this area, building scattered places different functions in the design of cabling, to be able to meet all of these different buildings, different application requirements, we need the entire cabling system to conduct a comprehensive in depth design considerations.
 

Figure 1: Cabling System Design
 

On campus cabling system , according to the classification of schools located in differnet, differnet mission, teaching different functions, as well as regional and other characteristics of different regions, each school has a different more or less cabling place. However, there are several points which can be used as colleges campus cabling system to explore the commonalities, but also can be used as a variety of colleges and universities can learn from campus cabling system solutions.

 

1. Campus Cabling Diversity

 

a. Building diversity

 

We also mentioned earlier, in the campus, especially college a wide variety of buildings, each building its building types and architectural features may vary. Some twenty or thirty or more layers of tall buildings (such as the school's main building, complex building, etc.), while others are one, two dwarf room (such as canteens, etc.); Some large bay, less information building (such as school gymnasium, etc.); While others are small spaces, intensive information construction (such as multimedia classrooms or computer training room, etc.). For such floor height varies, of various sizes, the number of different information points, we have to make different plans. For high rise buildings, for the convenience and savings trunk cable laying wires, equipment room locationi will need to be carefully considered, such as computer room location is set to the middle of the building. And you do not need low building special consideration. For information point-intensive construction, telecommunications room on each floor of its location also needs attention. Because if you set reasonable, we can save a lot of horizontal cable; What's more, if too much information points in the same layer, also need to consider setting up multiple telecommunications rooms. For large bays place, not only to consider the distribution of information points, but also consider wheter there is the level of information points length over 90 meters, if there are more than 90 meters of the situation, we need to consider the use of fiber optic cable or increase between telecommunications solutions. Also, in some campus gymnasium, auditorium and other places, also need to consider whether to set CP boxes and other issues.

 

b. Application of diversity

 

In colleges and universities, the diversity of buildings, each building determines the variety of applications. Such as teachers' apartments, student dormitories, school comprehensive building, administration building, a variety of different teaching building, laboratory building used for research, data storage and computing centers. Applications and their information needs are very different. So many applications need not buildings and places, they must be designed according to different requirements. Teachers apartments, student dormitories according to ordinary residential buildings can be cabling design; househole classroom or every student dormitory apartment, basically meet a data point, a voice can be. Comprehensive building, administration building can be carried out according to the way commercial office planning and design; In addition to meet the demand of each office's basic data, voice, consider increasing the internal campus network information in a specific department, such as education private network information point requirements. A variety of conferentce rooms, reception and other areas, need to consider adding wireless AP points. Data storage and computing centers can be designed according to the data center, to meet a variety of information throughout the campus switching, aggregation and storage. The experimental and research laboratory building as an important place, which may have strong radiation, corrosive material existence, there may exist high temperature, humidity, shock and vibration environments, there may be the most dangerous biological virus. Therefore, their application and requirements may be much more than we usually say ten categories of construction areas, so for special programs. To take into account not only the electromagnetic interference, environmental impact, but also consider the potential life safety issues. Therefore, these sites suggest using the whole screen or fiber class industrial grade high flame retardant wiring products, such as using fire-retardant grade reach CMP / OFNP grade, industrial grade reaches IP67 cabling products.

 

2. High-speed transmission of Information

 

High speed transmission of information for campus cabling system is already a pressing task. A variety of multimedia transmission, video transmission and other large flow of data communication more and more. For school on the high speed network transmission channel is essential. Including multimedia educational system, remote network education system, digital libraries, data centers and other places, is information is very concentrated, at least to ensure Gigabit to the desktop, Gigabit backbone. Under the condition of the budget allows, it is best able to do Gigabit to the desktop, 40G/100G as the backbone for future development needs. For classroom apartment or student residence, it should try to make Gigabit to the desktop requirements. Because who knows, in the next 5-10 years, or longer period of time, how fast development of the Internet? telematics what would happen to the great changes? Campus Network what will change? So in product planning, to do not only meet the existing information and communication needs, but also to do with a certain forward looking.

 

3. Stability and Security of Information

 

In the campus network, the reliability and security of information transmission is very important, because it not only directly related to the use of campus communications network, but also to the entire campus of internal and external education system problems. Which may affect the security of network communications to the national education system. Instability in the event of information or information leaks, not only caused the affected education, and may bring significant social problems. Such as school entrance examination system due to system instability problems, or important information or test data within the education sector was stolen during transmission and so on. So campus intranet for information requirement is in any case have to ensure that the information transmitted high reliability, high security. In the planning and design of the campus cabling must be to choose a good quality cabling products, but also in fiber optic cabling system to avoid interference or disclosure of information. Achieve stable performance, reliable transmission of information security.

 

The Campus Cabling System Considerations

 

1. Disaster preparedness

 

Disaster prevention, for any cabling system is need, and also is necessary. On campus cabling system, pay attention to disaster prevention and many, such as earthquakes, lightning, flood, fire, etc. Around the school to the actual situation may have different, but in the integrated wiring system, the following two disasters have a very important relationship.

 

a. Lightning Stroke

 

Campus cabling system is different from general cabling system is one of the local architecture is numerous, wide distribution. Each building and interconnection of information between, or the information architecture and data center interconnection, must pass a variety of outdoor communication cables, so the campus backbone cable corresponding increase, which gives the outdoor cabling lightning protection challenges. Because once a root trunk cable struck by lightning, and the grounding system in case of a problem or did not do, when hundreds of thousands of volts high voltage transient will pass along the cables between devices, resulting in equipment damage, data lost, resulting in significant losses. So into the line of good grounding system and surge protection is very important. Of course, if you want to achieve more secure, avoid outdoor cables in danger of being struck by lightning can also be used outdoors in all non-metallic reinforcing outdoor fiber optic cable.

 

b. Fire Disaster

 

In addition to natural disasters, the current fire casualties and property loss is caused by the most serious disasters. On campus, most of the buildings are crowded places. In addition to selecting a variety of fire related materials and good fire prevention measures, cabling system cables fire retardant also has become essential. Because as the demand for information transmission, communications cable in the building has more than the number of number of strong electric cables trend, but the communication cable fire retardant has not been given due attention.

 

In addition, for campus cabling system, others, such as the computer room of the need to guard against seismic reinforcement, cables rat bite, etc., also need to pay attention.

 

2. Management 

 

For school cabling systems, too much applications, and wide distribution of information points, application and needs vary, which brought the system management and maintenance of a great test. The traditional label drawing and handwriting management, or use the computer for documentation and preservation of the way, for such a large cabling and preservation of records in a timely manner, it is very difficult. Therefore, within the scope of the budget allows, it is recommended universities such as large scale cabling system uses intelligent infrastructure management system to improve cabling system maintenance and management, and enhance network security.

 

3. Intelligent Building digitized

 

In campus intelligent cabling, in addition to our previously mentioned, but also includes the campus radio systems, fire alarm systems, electronic fence system, monitoring system, LED large screen display systems, etc. These systems are in the transition to digital. Because of a digital campus will be teaching, research, management, technical services, services life and campus information collection, processing, integration, storage, transmission and application, so that the use of digital resources are fully optimized. By implementing from the environment (including equipment, classrooms, etc.), resources (such as books, handouts, courseware, etc.) to the application (including teaching, learning, management, service, office, etc.) all digitized, in the traditional campus built on a digital space to improve the operating efficiency of the traditional campus, expanding the traditional campus business functions, and ultimately the overall educational process information, so as to improve the management level and efficiency. Therefore, the campus all variety of intelligent system based on transmission channel will also jumped to Gigabit, and even Gigabit network requirements. In the design and planning, and perhaps to consider the application of digitization. In which the product can be selected copper Category 6, cat 6a, cat 7 products, fiber optic cable in OM3 OM4 multimode and singlemode cable and other fiber optic products. However, for fire alarm systems, campus broadcasting system, and its products should be chosen to meet the high flame retardant properties, if possible, it is best to choose a high fire retardant cables. Because it does not lead to a fire occurs due to the rapid combustion of the cable causes the system to malfunction.



Figure 2: 305m Bulk Cat6 550MHz Cable UTP

 

Conclusion

 

Campus cabling system though complex, but as long as we grasp the core features of cabling system, clear the standard cabling system the basic requirements, specifically the various buildings, the application of the various systems and functions. It is not difficult to design and planning. Even the school have dozens, hundreds buildings, even if there are many school of information and communication applications, the final analysis are inseparable from the basic principles of cabling. Therefore, cabling system in the school, in order to maximize long as we grasp little less to more of the principles from the point to the line, from a line to a plane unfold. You will find, and then a big projects, the final show in front of us or our common and often do a single type of building cabling system, just follow their individual needs and applications for planning and design, you can complete set of perfect school cabling system.

 

 

For more information on cabling, please visit http://www.optoroute.com.cn/

The Lessons drawn from Cable Design

Introduction

 

As all we known: cabling of building local area network (LAN) at the end of the 100m cabling, community area last 2km integrated network cabling computer data center room, such as several internal cabling. Cabling in different locations, in accordance with their purpose and corresponding transmission index calculating the length of the cabling to allow laying. No matter what position cabling used, all belong to the city telecommunications network extension and an important part. Only in depth understanding of urban development trends of telecommunication networks, in order to accurately grasp how to design integrated cabling; also only be taken with the city development strategy telecommunication network synchronization and with suitable, Cabling can really play the overall effectiveness of the network and obtain win-win enconomic effects. Here only to the development of telecommunication networks, Cabling should be synchronized with the development, as well as the latest developments in cabling issues such as study and discussion.

 

The development trend of telecommunication network

 

In traditional telecommunications networks based voice communication, a small amount of digital data network (DDN), Frame Relay (FR) point to point, such as low rate of data communication, a voice path begins only within the bandwidth of 64kbps. In the early 1990s, China's foreign experience with the introduction of Ethernet cabling and network communication technology, and accordingly developed our standards, and actively promote the application of the telecommunications network to get great propress. In just 10 years time, network communication technology from 10 megabytes, 100 megabytes, Gigabit to 10 Gigabit-class development, or even 10 Gigabit-class network will soon put into large-scale application.

 

The development of the telecommunication network is omni-directional, methods of communication include: wired, wireless, satellite, etc.; Communication contents include: telephone, television, data, etc.. 

 

a. The rapid development of the passive optical network (PON)

 

Currently, the passive optical network (PON) is rapidly developing country, for example: EPON (Ethernet Passive Optical Network), GPON (Gigabit Passive Optical Network), GEPON (Gigabit Ethernet Passive Optical Network), APON (ATM Passive Optical Network), BPON (Broadband Passive Optical Network) and other network applications, structured cabling will have a direct impact. Now illustrate EPON/GPON networking mode:

 

EPON/GPON is mainly composed of OLT (Optical Line Terminal), ODN (Optical Distribution Network) and ONU (Optical Network Unit) and other components. EPON / GPON networking shown in Figure 1:


Figure 1 shows EPON/GPON networking model



Figure 2 shows ODN optical channel model

 

The network characteristics of EPON/GPON

 

* On the OLT and ONU in addition to optical interface, combined with GE (Gigabit Ethernet), FE (Fiber optic Ethernet), RF (Radio Frequency), E1 (2.048Mbps) interfaces, can be applied to various network applications.

 

* EPON can provide uplink and downlink symmetrical rate 1.25Gbps.

 

* GPON can provides uplink 155Mbps, 622Mbps, 1.24Gbps or 2.48Gbps; Downlink 1.24Gbps or 2.48Gbps.

 

* Public IP network signal WDM technology, the uplink of 1490nm and downlink of 1310nm signal through the central office OLT integrated transceivers were injected into the same optical fiber, through the optical distribution network ODN spending 32.64 points or 128 optical link to the corresponding ONU. If necessary, can also be injected CATV signals using the third wavelength of 1550nm central office OLT transceiver integrated in the corresponding ONU than the client integrated transceivers separated by the RF interface of the user received a cable distribution network.

 

* EPON/GPON network support tree, star, bus, hybird and redundant topology etc..

 

* EPON is based on the standard Ethernet technology and IEEEP802.3ah, in the case of transport 1.25Gbps data stream, the optical line terminal (OLT) and the optical network terminal (ONU) between a transmission distance up to about 20km.

 

* GPON is based on the ITU-T standard G984.1-G984.5 version, is preferred in Europe and North America, FTTH technology, is being used worldwide. GPON generic framing protocol that provides a multi-protocol transmission efficiency can provide an open interface, with 2.48Gbps rate symmetric and asymmetric transmission capacity, OLT/ONU transmission distance up between 37km.

 

b. FTTH or FTTB/N

 

As EPON/GPON technology matures, the price of fiber optic cables are more and more cheap. Fiber optic cable extends to the floor, community nodes, and even to the family increasingly likely. As telecom companies certainly want to consider the relationship between input and output in the short term cost recovery and profit is the ultimate goal. 

 

The advantages of FTTH solutions

 

1. Provide greater bandwidth capacity, suitable for high speed network applications.

 

2. Is not affected by the outside electromagnetic interference, anti-interference performance is good, high quality communications.

 

3. Silica fiber material production inexhaustible.

 

4. The price of fiber optic cable has lower than copper (but photoelectric conversion equipment price is still relatively high, therefore, the overall cost is higher).

 

The disadvantages of FTTH solutions

 

1. Same scale projects, the initial investment is higher.

 

2. New fiber optic cable and more, longer construction period (relative to the FTTB/N solution).

 

3. Slow return on investment.

 

For more information on Cabling, please visit http://www.optoroute.com.cn/

How to protect DWDM Network Security through Optical Switch Protection System

DWDM system in the trunk and local fiber optic transmission network has a large number of applications. Due to the amount of traffic carried by focus on the importance of safety more and more attention in the event of full resistance will affect all business network hosted. The DWDM network security has always been the most important in the transmission maintenance work.

But DWDM protection technology by its own limitations, there is not flexible, large investment, the effect is not ideal problem, and therefore has played a very important role in light switch protection technology introducing. This article describes the basic principles of optical switching technology and protection technology trends, in practical application, large-scale use in the current network to improve network security.

The DWDM network protection: protection optical channel 1 +1 or 1: n protection OLP protection, dual-selective receiving and sending and receiving two-way selection protection. These methods can effectively improve the security of the network, but the cost is relatively high, relative to other levels of protection is not flexible enough. In practical systems, optical fiber, optical cable reliability than the reliability of the device differential protection system only, rather than for line protection, the practical utility is not too large. Therefore, a convenient, flexible, small investment light automatic protection technology came into being, it can effectively solve the protection issues, economic, practical, safe and protect the network.

Optical switch protection system for the security of communication network provides a set of economic, practical solutions, the formation of a non-blocking, high reliability, flexible, anti-disaster ability of the optical communication network. Optical switch protection system by the automatic switching and network management stations, you can achieve light switch protection, monitoring and the optical path of the optical power emergency dispatch three main functions.

The Optical switch protection system switching control module is a set of optical switches, optical power monitoring, stable light source monitoring in one of the high level of integration modules. Optical power monitoring module and optical switch control module coordination, selection of splitting ratio of 97:3 is more appropriate on the trunk, the equivalent of approximately 0.2dB attenuation on the transmission line; optical switching module contains 1x2 or 2x2 Optical switch, controlled by the switch between the main and backup light routing operation.

Real-time monitoring of the optical power monitoring module communication optical fiber optical power value reported to the main control module; analysis and comparison of the main control module, found that the change in value of the optical power exceeds a preset threshold switching immediately issued instructions to the optical switch module; optical switch module by the Directive instantly switching action has occurred. In order to achieve a switching operation.

The optical path automatically switch protective equipment involved in trunk transmission system did not affect the transmission characteristics. In fact, switching equipment involved in the optical switch and splitter only two passive optical devices.

One end of the switching unit is connected to the transceiver of the transmission system, the main fiber optic cable and the spare cable, respectively connected to two output terminals of the 2x2 optical switch. When the optical path occurs when the optical power is abnormal, the optical switch is automatically switched to the alternate route.

It is understood that the optical switch protection system has the following advantages. Fast switching speed, the optical switch switching speed ships 5ms, plus system analysis, the response time of a single-ended switching time of less than 20ms, the switching time of less than 50ms for the entire system, the basic switching operation can be done without interrupting the communication, to achieve business grade level of protection.

Switching, high reliability, implemented through the optical power monitoring, to avoid false alarm of the optical frame, ensure switched judgment is correct. The spare fiber routing monitoring, to ensure the validity of the switch, and continue to be monitored after switching optical path.

Emergency dispatch function, simply switching command issued from the program, you can deploy routing to facilitate the realization of the non-blocking cutover and line maintenance work. The switch device for a transmission system is transparent, i.e. the switching device does not require the type of transmission system can use either SDH or DWDM.

The optical switch protection DWDM is an economical and safe a line protection method, but the the light automatic protection system intervention to DWDM systems, there are many issues to consider. Splitter 97:3 spectral, optical switching device insertion loss is about 2 dB intervention light switching device, the system has an additional two light jump fiber insertion loss is estimated as 1 dB, so the whole switching device Interventional theoretically maximum will bring 3dB attenuation, and many cases of practical use only in 1.5-2.5dB. Primary and backup routes throughout the uniform attenuation, the attenuation of the primary and backup routing line difference is very small, the system standby line without consideration. If the attenuation of the alternate route is too large, you need to consider alternate route EDFA, to zoom in the standby line. Larger principle is that the alternate route than the main line of the route attenuation how much, the EDFA on compensation. Of course, EDFA generally leave a margin adjustable.

Signal-to-noise ratio OSNR values. 2.5G system, for example, if there is no FEC function, OSNR> 20dB; FEC function, OSNR> 16dB. 10G system if there is the the FEC function OSNR> 20dB. Intervention light switching equipment, the full attenuation will be reduced by 3 dB OSNR value of the system will also be reduced by 3 dB when the DWDM system is still able to meet the opening requirements, you do not need to intervene EDFA. If you can not meet the demand of the opening of the DWDM system, the need to intervene in the EDFA optical amplifier EDFA intervention, although the increase NFEDFA (Usually take 5.5dB), but also reduces the full attenuation of the line and to improve the light emitting power of a single wave, the overall increased slightly on the OSNR value than before the intervention.

Fiber dispersion coefficient to measure the dispersion coefficient is two wavelength interval of 1 km of the a 1nm two lightwave transmission length of the optical fiber to reach the time difference, in units of ps/nm·km. G.652 fiber dispersion coefficient to 17 ps/nm·km G.655 fiber dispersion coefficient of 6.5ps/nm·km, the 2.5G signal generally does not require compensation. 10G signal is relatively small due to chromatic dispersion tolerance, 10G rate signal on G.652 fiber transmission distance of more than 30km on the need for dispersion compensation, the G.655 fiber transmission distance of more than 100km may be compensated. The principle of dispersion compensation is necessary to leave after 10 to 30km margin dispersion compensation, the best dispersion compensation dispersion tolerance of alternating positive and negative, the best results.

Break placed currently used made of a dispersion-compensating fiber (DCF), dispersion compensating module (DCM) periodically so that the accumulated dispersion close to zero dispersion compensation fiber link. In general, the amount of dispersion of the preparation route should be considerable and the main route. Need to pay attention to the DCF fiber insertion loss is generally relatively large, it is generally DCM modules used together with the EDFA.

Optical automatic switching system for the DWDM line protection is both safe and economical means of protection. The future, as the size of the network continues to expand, light switch protection systems will play a more important role to meet the requirements of the assessment indicators, to improve the safety of operation of the transmission network.

The actual situation, DWDM is bound to play an important role in the optical transmission network, EDFA and fiber optic technology continues to evolve, the optical transmission system to overcome the obstacles of the optical signal attenuation and dispersion, to achieve the long-distance non-renewable transmission. New technologies continue to emerge, will promote the DWDM transmission lines applied to the development of all-optical network applications.


For more informaion on DWDM, please visit http://www.optoroute.com.cn/

How is Optical Switching Technology use in the Communication Network

Fiber optic network, as synonymous with high-speed and effective in the communication system has been for a large scaled deployed and applied. However, the transparent, high survivability of optical communication network is a goal of broadband communication network. Optical switching technology as an important foundation for all-optical communication network technology, its development and application will greatly affect the development direction of future optical communication networks. 

 

Advantage of optical fiber communication is the huge capacity and strong anti-jamming capability, superior performance of which has already been confirmed, and in modern communication systems gradually replace the electronic circuits in the past as the main components of the communication network, becoming an important component of modern communication.

 

Optical switching

 

The optical signals are multiplexed in three ways, space division, time division, and WDM, the corresponding optical switching methods space division switching, time division switching and wave division switching to complete the three multiplexed channels.

 

The space division switching is the domain swap space on the optical signal, the basic functional components of the spatial light switch. Spatial light switch is the principle of optical switching components gate array switch can be in any of the multiple input multiple output fiber established path. It can constitute an empty spectroscopic switching unit, and other types of switches can also together constitute a time-division switching unit or wave stars. Empty spectral switches generally have both fiber-based and space-based space division switching is a division of swap space.

 

Time division multiplexed signal multiplexing method is a communication network, a channel is divided into a number of different time slots, each optical path signal distribution occupy different time slots, a baseband channel to fit the high-speed optical data stream transmission. Need to use time division switching time slot interchange. The time slot interchanger of the input signal is sequentially written to the optical buffer, and then read out in accordance with established order, thus achieving a one frame at any one time slot exchange to another time slot and outputs completed the timing exchange program. Usually bistable lasers can be used as an optical buffer, but it is only the bit output, and can not meet the demand of high-speed switching and large capacity. While the optical fiber delay line is a more time-division switching device, the time-division-multiplexed signal light input to the optical splitter, so that each of its output channels are only a light signal of the same timeslot, then these signals combined through different optical delay line, after a signal of the type of delay line to obtain a different time delay, the final combination fits before the signals are multiplexed with the original signal, thereby completing a time-division switching.

 

Ships in WDM systems, the source and destination are required to transmit signals using the same wavelength, such as non-multiplexed so multiplexed in wavelength division multiplexing technology is widely used in the optical transmission system, each multiplex terminal using additional multiplexers, thus increasing system cost and complexity. In the WDM system, wave spectral exchange in the intermediate transmission nodes, to meet no additional devices to achieve wavelength division multiplexing system source and destination communicate with each other, and you can save system resources, improve resource utilization rate.

 

Wave spectroscopic switching system first lightwave signal demultiplexer is divided into plural wave splitting is required to exchange the wavelength channels in each channel wavelength switching the last signal obtained after multiplexing composed of a dense wave division multiplexing signal from an optical output, which take advantage of the characteristics of the fiber-optic broadband, low-loss band multiplexing multiple optical signals, greatly improving the utilization of the Fiber Channel, to improve the communication system capacity.

 

Hybrid switching technology is used in large-scale communication network in a variety of the optical path switching technology a mixture of multi-level link connection. In large-scale networks need to be multi-channel signal splitter and then access different link, making the advantages of wavelength division multiplexing can not play, so using wavelength division multiplexing technology levels connecting link, and then space division switching technology used in all levels of link exchange to complete the interface between the link, finally destination and then wave of the exchange of technical output corresponding optical signals, signal combined final sub output. Mixed-use switching technology time mixed, air separation - after midnight - wavelength division mixed several minutes - hours of mixing, air separation - wavelength division.

 

All-optical network switching technology

To realize the all optical network switching, the first is to use the circuit switch based optical add-drop multiplexing (OADM) and OXC (optical cross connect) technology to achieve wavelength switching, and then further realization of optical packed switching.

 

Wavelength switching is based on wavelength in units of optical circuit switched domain, wavelength switching optical signals to provide end-to-end routing and wavelength assignment channel. Wavelength switching key is to use the corresponding network node equipment, optical add-drop multiplexing optical cross-connect. Optical add-drop multiplexing the working principle is based on all-optical network nodes drop and insert the required wavelength path. Its main constituent elements of the multiplexer reconciliation multiplexer, as well as optical switches and tunable harmonic, etc.. Optical add-drop multiplexing of the working principle and the synchronous digital hierarchy (SDH) multiplexer separate interpolation function is similar, but in the time domain, while the other is acting in the optical domain. The optical cross-connect and the synchronous digital system digital cross-connect (DXC) similar effect, but to achieve the cross-connection to the passage in the wavelength at which the optical network node.

 

Optical wavelength to exchange essentially took office contingent is not efficient optical switching, connection-oriented attribute it established wavelength channel re-distribution to achieve maximum utilization efficiency can not be achieved, even if the communication is idle. Optical packet switching can be implemented with a minimum switching granularity multiplexing of bandwidth resources, improve the communication efficiency of the optical network. Optical packet switching is generally light and transparent packet-switched (OTPS), optical burst switching (OBS) and optical label switching (OMPLS). The optical the transparent packet switching characteristics is the packet length is fixed, the use of synchronous switching manner, the need for all input packets are synchronized in time, thus increasing the technical difficulty and increase the use of cost. The transmission optical burst the use of a variable-length packet data transfer header control information and separated in time and space, to overcome the shortcomings of the synchronization time, but it is possible to generate the packet loss problem. Optical label switching is carried out to add a tag in the IP packet in the core network access re-packet, and the routing method according to the tag inside the core network.

Although optical switching communication Occasion require a higher (generally more than 10Gb / s) is more suitable for lower transmission costs and greater system capacity can be achieved; via digital transmission rate when the system requirements require a lower transmission rate (2.5Gb / s or less), the connection configuration more flexible access may be more appropriate to use the old-fashioned way of photoelectric conversion. Therefore, the practical application of the current should be selected according to the application scenarios appropriate system deployment.

 

With the future communication network technology development and all-optical network, optical switching technology will be more innovative and more efficient ways for communication network photochemical contribute to become an important part of social development and people's lives.

 

For more information on optical switching, please visit http://www.optoroute.com.cn/

Mux and Demux Used in FTTH (Fiber To The Home) network

This transition from copper to fiber optic cabling is called FTTx (Fiber To The x)where x is determined by the distance between the optical fiber and the end user.

There are five most known FTTx architectures:

- FTTN Fiber To The Node

- FTTC Fiber To The Curb

- FTTB Fiber To The Building

- FTTH Fiber To The Home

In FTTH configuration the optical signal reaches the subscriber’s home or office and it is distributed by copper wiring or wireless connection. The replace of copper wires by optical cables offer to customers:

- Very wide bandwidth (1013 to 1016 Hz)

- minimal interference from neighboring sources

- Low transmission losses

- Increased signal security, because it is harder for an “adversary” to “eavesdrop” a light signal

Wavelength Division Multiplexing
 

WDM (Wavelength Division Multiplexing) is a technique similar to FDM (Frequency Division Multiplexing) which is used widely in Fiber To The Home networks While FDM combines various frequency carriers and sends them through a single copper cable, WDM combines various wavelengths and couples them into a single optical fibre. The two multiplexing techniques are similar because frequency and wavelength are connected by the equation λ=V/F , where V is the monochromatic beam's speed. The adoption of WDM enables the operator to expand the network's capacity without deployment of extra fiber cable. Furthermore A WDM optical channel can carry any transmission format.

 

The wavelength multiplexer at transmitter's side merges the input signals and passes them through the optical fiber. The signal is amplified by an EDFA or Raman amplifier and is separated back into individual output wavelengths at the wavelength demultiplexer at receiver's side. The separation of wavelengths at the demultiplexer is achieved by the use of interference Fabry–Pérot optical filters. These filters are two plane reflecting surfaces which contain air or other material between them. The separation of wavelengths is based on interference between the reflected beam and the two surfaces. The interference can be either constructive or distructive. Constructive interference occurs when the phase difference of transmitted waves is zero while distructive when δ≠0, where δ is the phase difference.

 

CWDM multiplexer
 

The Coarse wavelength division multiplexer has a channel spacing of 20nm and using the wavelengths from 1270 up to 1570nm. It features low insertion loss and low polarization depended loss (PDL)<= 0.1dB. When the polarization state of an incident wave changes, the output power is also changes. This is the concept of PDL and its calculated by the equation:

PDL = 10log(Pmax/Pmin)

where the fraction Pmax/Pmin is the peak to peak difference in power of an optical signal with respect to its polarization state. CWDM multiply the capacity of existing singlemode fibers by combining up to 16 ITU-T G.694.2 compatible channels in metropolitan access and enterprise networks and for CATV applications. They are a low cost approach for systems that use imprecise laser sources and are an alternative to more expensive DWDM components.
 

DWDM multiplexer
 

Dense wavelength division multiplexer (DWDM) has channel spacing of 100 or 200 GHz. It uses precise laser source which creates channels with very close spacing. It operates within the 1550 nm band and can drastically increase the capacity of an optical network. The equipment which is used in a DWDM system consists of high precision lasers, multi wavelength optical repeaters (MOR) and Erbium doped Fiber Amplifiers (EDFA). Nowadays the MOR became obsolete and EDFA are used instead, for signal amplification.

 

Add/drop

Both CWDM and DWDM multiplexers supports the add/drop function which adds or removes a single wavelength from an existing data stream.

 

For more WDM information, please visit http://www.optoroute.com.cn

 

 

 

How Does WDM-PON Optical Access PON

PON technology developed with two directions, one is single wavelength higher transmission rate, such as 10G EPON and XG - PON; Another is the single fiber transmission multiple wavelengths, namely the WDM - PON technology industry high attention. And WDM-PON is a combination of WDM technology and the advantages of PON topology structure, developed into a high performance access way.

Since the emergence of PON and years of development, it formed the BPON, EPON, GPON, WDM - PON and a series of concepts. WDM - PON EPON and GPON has many advantages: saving the cost of optical fiber and OSP, transmission distance is longer, the fiber optic network is simpler; It combines the advantages of WDM technology and PON topology, developed into a high performance access way. Though the WDM - PON production chain is not mature, and the price is not high, its future prospects is bright.

Along with the national broadband strategy, the "broadband China" and "three net fusions" further develop. PON access technology plays an increasingly important role. Compared with and the mainstream EPON/GPON comparison, WDM - PON PON has many advantages

1.Cost saving
(1) EPON/GPON each optical fiber carrying two wavelength (1490nm and 1490nm);
(2) WPON two-way carrying 16 ~ 64 C + L band wavelength, save fiber resources between 16 to 64 times.

2. The fiber transmission distance is longer
(1) 27 db EPON/GPON optical power fiber transmission distance is about 20 km;
(2) the WDM - PON 27 db fiber transmission distance of optical power budget is up to 63 km.

3. Compared to EPON/GPON networks, the WDM - PON is simpler, completely transparent in speed, business, and the expandability, safer and easier to maintain.

However, the development of WDM - PON also has difficulties: standard, the industry chain and cost performance.

1. The standard has not been formed: slow development of WDM - PON is a major cause of failure to form a standard. Currently, standard organizations and manufacturers only on WDM - PON reached consensus on the two functions, one is to introduce the principle of wavelength division fiber access system, the second is to use of point to multi-point network topology. And for the formation of the WDM - PON standards also need a period of time.
2. Industrial chain is not yet mature: WDM PON technical basically has two factors, one is the complicated environment on the WDM-PON AWG strict requirements, the second is how to meet the demands of fiber transceivers,such as SFP transceivers and GBIC transceivers.
3. The price has no advantages: because the manufacturer of the WDM-PON equipment is less, the device manufacturer also less, the lack of competition mechanism, the price is on the high side. From the point of new economy analysis, WDM-PON cost per user is still now about three times of EPON/GPON technology.

From WDM-PON market development situation at present, internationally, so far most of the WDM - PON network deployment in South Korea. Korea telecom (KT) is the most active operators deploy WDM-PON.

WDM - PON technology in the practical application has shown good performance and application prospects, including NTT, KDDI, Verizon and some operators in Europe also expressed a keen interest in WDM-PON, and plan to choose WDM-PON as candidates for the next generation access fiber optic network technology solutions, including the Netherlands UNET FTTB commercial network, already deployed using WDM-PON for high-end business users provide better service. WDM-PON commercial process will produce a great impetus, make its future application more clear.

For more poduct informaton, please visit http://www.optoroute.com.cn

Fiber-optic network multiplexing- DWDM

 

Today, disaster backup is an important issue, and how to ensure that the data center as soon as possible recovery operations after a certain level of failure and disaster, is essential for some of the business continuity sensitive enterprise.

 

Disaster backup most use the city off-site disaster recovery. Depending on the user's business difference, the designed disaster recovery solution is very different.  For remote disaster recovery solutions, some host-based or based on storage replication via TCP / IP reliaze offsite backup.

 

Howere,TCP / IP network is not very stable, may occur packet loss, so  to achieve copy need a variety of ways such as fiber optic channels or ATM technology, that can reach the long-distance disaster recovery system,  from more than ten kilometers to tens of kilometers or even thousands of kilometers can achieve both disaster recovery system.

 

This technology we calle it fiber-optic network multiplexing - DWDM. Let's see DWDM how to work in a disaster recovery environment via a specific case of disaster recovery.

 

DWDM disaster recovery applications

 

We see a typical SAN environment, we have 2 hosts, 2 SAN switches, storage, they might HA, RAC environment may be stand-alone, this is not important now. Importantly, the SAN environment, we are generally configured locally, similar to a local area network, we have adopted the general line of fiber-optic connections can build a SAN environment.

 

Now, because business needs, you must consider disaster recovery. You want make these two machines, two storage distributed in a different room, however, these two rooms separated by more than 10KM.If were forcibly opened, we will seelike that:

 

We can see there are a lot of fiber needs to be pulled very long, but these long fiber must be rely on the carriers generally to pull. Moreover, more of the optical fiber will bring the greater the cost. Then do we do not have a good solution to this? Yes, this is DWDM fiber optic multiplexing (DenseWavelength-Division Multiplexing, high-density multi-work-point filter), according to the WDM development over DWDM technology has been widely used for many years, using DWDM SAN diagram will become like that:

 

The principles of DWDM principles

 

As for the Fiber multiplexing, long-distance fiber-optic lines now need only one fiber, just to consider the redundancy, as long as the two fiber. After this, the entire structure has not changed, you can think of that fiber line run multiple fiber you need.

 

DWDM is how to achieve it? We can look at a schematic:

 

The DWDM is actually using different wavelengths in a fiber optic line to pass different data, to simulate different channels actually look like different fiber communication. As long as the wavelength is not same, so DWDM casually can multiplexing dozens of channels in a fiber optic line At laboratories can even reuse the thousands of channels.

 

So with DWDM access to remote storage via SAN becomes very easy, remote RAC is no longer a dream. In fact, through this DWDM technology, and then use the volume replication to disaster recovery technology has been officially in use in the domestic banking institutions. Moreover, the remote RAC, a new disaster recovery plan, which can achieve high availability and Load balancing, and disaster recovery program, also consider using in the company.

 

For more DWDM information, please visit http://www.optoroute.com.cn

Things You Should Know About Fiber Optic Splitters

    What Is Fiber Optic Splitter?

Fiber optical splitter, also named beam splitter, is a integrated waveguide optical power distribution device, which splits the optical power carried by a single input fiber into two or more output fibers.  Splitters contain no electronics nor require power. They play an important role in passive optical network (EPON, GPON, BPON, FTTX, FTTH etc.) and are available in a variety of split ratios, including 1:4, 1:8, 1:16, and 1:32. Figure 1 illustrates a simple 1:4 optical splitter.

                                         
Fiber optical splitter, is different from WDM (Wavelength Division Multiplex). WDM divides the different wavelength fiber optic light into different channels. Fiber optic splitter splits the fiber optic light into several channels.

Fiber optical splitter, splits the fiber optic light into several parts at a certain splitting ratio. For example, a 1X4 equal ratio splitter. can split the fiber optic light signal into four equal 25% parts and sent to the 4 different channels. Fiber optic splitters can be terminated with different types of connectors, the main package could be box type or stainless tube type, one is usually used with 2mm or 3mm outer diameter cable, the other is usually used with 0.9mm outer diameter cables.

Fiber Optic Splitter Features

1. Single mode, multimode, and PM fiber types
2. Multiple port configurations, custom length and cable diameters
3. Various splitting ratios, 50:50 to 1:99
4. Tube type or Box type, PLC fiber optic splitters or Fused fiber optic splitters
5. PC, UPC, and APC fibre optic connectors
6. Available with FC, SC, ST, LC, and MU connectors

Types Of Fiber Optic Splitters

According to the working wavelength, optic splitters can be divided into single window fiber optic splitter and dual window fiber optic splitter.
Single Window Fiber Optic Splitter and Dual Window Fiber Optic Splitter
Here the window refers to the working wavelength. Single window fiber optic splitter is with one working wavelength, dual window fiber optic splitter is with two working wavelength. For multimode fiber, the term means that the fiber is optimized for 850 nm and 1310 nm operation. For single-mode fibers, the term means that the fiber is optimized for 1310 nm and 1550 nm operation.

From a technology stand point, there are two commonly used types of optical splitters: Fused Biconic Tapered (FBT) splitter and Planar Lightwave Circuit (PLC) splitter.

FBT splitter: Operating wavelength, Operating bandwidth, typical additional loss, insertion loss, polarization dependent loss, uniformity and directivity and splitting ratio
PLC splitter: Operating wavelength, insertion loss, uniformity, return loss and polarization dependent loss

FBT Splitter
FBT splitter is a traditional technology in which two fibers are placed closely together and fused together by applying heat while the assembly is being elongated and tapered with over 20 years history. It is a mature products, material used to make such products is easy to get so the total cost is small. FBT splitters are widely accepted and used in passive networks, especially for instances where the split configuration is smaller (1x2, 1x4, etc).

PLC Splitter
PLC splitters are developed based on silica glass wave-guide process with reliable precision aligned fiber pigtail in a miniature package. Waveguides are fabricated using lithography onto a silica glass substrate, which allows for routing specific percentages of light. PLC fiber splitter can realize 1X32 splitting or more and its loss is not sensitive to the working wavelength. PLC splitters offer very accurate and even splits with minimal loss in an efficient package.

A drawback of FBT technology occurs when larger split configurations (1x16, 1x32, 1x64, etc) are required.  FBT technology is limited in the number of quality splits that can be achieved in a single instance, so several must be spliced together when a larger split configuration is required. A more recent technology, PLC splitters offer a better solution for applications where larger split configurations are required.


Where Is OpticalSplitter Used?

Optical splitters are installed in each optical network between the PON Optical Line Terminal (OLT) and the Optical Network Terminals (ONTs) that the OLT serves. Networks implementing BPON, GPON, EPON, 10G EPON, and 10G GPON technologies all use these simple optical splitters. A PON network may be designed with a single optical splitter, or it can have two or more splitters cascaded together. Cascading is usually done when houses being served are clustered in smaller groups. Splitters are sometimes housed in the Central Office (CO) and individual fibers run from the office to each subscriber.

PON splitters are bi-directional, that is signals can be sent downstream from the central office, broadcast to all users, and signals from the users can be sent upstream and combined into one fiber to communicate with the central office.

Figure 2 illustrates a single splitter in GPON network. Note that the splitter can be deployed in the CO alongside the OLT, or it may be deployed in an OutSide Plant (OSP) cabinet closer to the subscribers. A splitter can also be deployed in the basement of a building for a Multiple Dwelling Unit (MDU) installation.

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