Network Crunch is Coming, How to Tackle?

                        

A European Union research project is looking at ways to expand by one-hundredfold the capacity of an optical fibre. The project will need to develop techniques to exploit multimode and specialist fibre, and if successful, will require new fibre deployments in the network.

Current 100 Gigabit-per-second (Gbps) dense wavelength division multiplexing (DWDM) systems are able to transmit a total of 10 terabits-per-second of data across a fibre (100 channels, each at 100Gbps). System vendors have said that with further technology development, 25Tbps will be transported across fibre.

But IP traffic in the network is growing at over 30% each year. And while techniques are helping to improve overall transmission, the rate of progress is slowing down. A view is growing in the industry that without some radical technological breakthrough, new transmission media will be needed in the next two decades to avoid an inevitable capacity bottleneck.

"The Shannon Limit - the amount of information that can be transmitted - depends on the signal-to-noise and the amount of power you can put down a fibre," says Ian Giles, CEO of Phoenix Photonics, a fibre component specialist and one of the companies taking part in the project. "You can enhance transmission capacity by modulation techniques to increase bit rate, WDM and polarisation multiplexing but in the end you run out of the ability to transmit more information along a single-mode fibre."

This 'network crunch' is what the MODE-GAP project is looking to tackle.


Project Details

One of the approaches that will be investigated is exploiting the multiple paths light travels down a multimode fibre to enable the parallel transmission of more than one channel.

These multiple paths light takes traveling in a multimode fibre disperses the signal. "The proposal we are making is that we take a low-moded fibre and select specific modes for each channel, or a high-moded fibre and select modal groups that are very similar," says Giles. The idea is that by identifying such modes in the multimode fibre, the dispersion for each mode or model groups will be limited.
But implementing such a spatially modulated system is tricky as the modes need to be identified and then have light launched into them. In turn, the modes must be kept apart along the fibre's span.
The project will tackle these challenges as well as use digital signal processing at the output to separate the transmitted channels. The project consortium believes that up to 10 channels could be used per fibre.

Photonic bandgap fibre has an air core that doesn't create scattering. As a result the non-linear threshold is some 100x higher, meaning that more power can be put into the fibre.


What Next?

The MODE-GAP project is still in its infancy. The goal is to develop a system that allows the multiplexing and demultiplexing of the spatially-separated channels on the fibre. That will be done using multimode fibre but Giles stresses that it could eventually be done using photonic bandgap fibre. "You then enhance capacity: you increase the number of channels, and decrease the non-linearities which means you can increase the amount of information sent per channel," says Giles.
"Up till the spatial modulation part, the system is the same as you have now," he adds. "It is only the spatial modulation part that needs new components." NSN will use any prototype developed within its test-bed where it will be trailed. "They don't want to reinvent their equipment at each end," says Giles.

The project will also look to develop a fibre-amplifier that will boost all the fibre's spatial separated channels.

The project's goal is to demonstrate a working system. "The ultimate is to show the hundredfold improvement," says Giles. "We will do that with multiple channel transmission along a single photonic bandgap fibre and higher capacity [data transmission] per channel."


Project Partners

In addition to NSN's systems expertise and test-bed, Eblana Photonics will be developing lasers for the project while Phoenix will address the passive components needed to launch and detect specific modes. OFS Fitel is providing the fibre expertise, while the University of Southampton's Optoelectronics Research Centre is leading the project. 

The other universities include the COBRA Institute at the Technische Universiteit Eindhoven which has expertise in the processing and transmission of spatial division multiplexed signals, while the Tyndall National Institute of University College Cork is providing system expertise, detectors, transmitters and some of the passive optics and planar waveguide work.
 

How Flexible Grid WDM Evolved?

  

WDM networks operate by transmitting multiple wavelengths, or channels, over a fiber simultaneously. Each channel is assigned a slightly different wavelength, preventing interference between channels. Modern DWDM networks typically support 88 channels, with each channel spaced at 50 GHz, as defined by industry standard ITU G.694. Each channel is an independent wavelength.

The fixed 50-GHz grid pattern has served WDM networks and the industry well for many, many years. It helps carriers easily plan their services, capacity, and available spare capacity across their WDM systems. In addition, the technology used to add and drop channels on a ROADM network is based on arrayed-waveguide-grating (AWG) mux/demux technology, a simple and relatively low-cost technique particularly well suited to networks based on 50-GHz grid patterns.
  WDM networks currently support optical rates of 10G, 40G, and 100G per wavelength (with the occasional 2.5G still popping up), all of which fit within existing 50-GHz channels. In the future, higher-speed 400-Gbps and 1-Tbps optical rates will be deployed over optical networks. These interfaces beyond 100G require larger channel sizes than used on current WDM networks. The transition to these higher optical rates is leading to the adoption of a new, flexible grid pattern capable of supporting 100G, 400G, and 1T wavelengths.

Current generation

The fixed 50-GHz grid pattern specified by ITU standards is shown in Figure 1. Any 10G, 40G, or 100G optical service can be carried over any of the 50-GHz channels, which enables carriers to mix and match service rates and channels as needed on their networks.
A look inside each channel reveals some interesting differences between the optical rates and resulting efficiency of the optical channel (see Figure 1). A 10G optical signal easily fits within the 50-GHz-channel size, using about half the available spectrum. The remaining space within the 50-GHz channel is unused and unavailable. Meanwhile, the 40G and 100G signals use almost the entire 50-GHz spectrum.

FIGURE 1. Optical rates and their spectral efficiency.

Spectral efficiency is one measure of how effectively or efficiently a fiber network transmits information and is calculated as the number of bits transmitted per Hz of optical spectrum. With 10G wavelengths the spectral efficiency is only 0.2 bit/Hz, while the 100G wavelength provides a 10X improvement in spectral efficiency to 2 bits/Hz. The more bits that can be transmitted per channel, the greater the improvement in spectral efficiency and increase in overall network capacity and the lower the cost per bit of optical transport.
While 100G wavelengths are becoming more common, carriers are already planning for higher-speed 400G and 1T channels on their future ROADM networks, with the expectation that spectral efficiency will at least remain the same, if not improve. New ways of allocating bandwidth will be needed to meet these expectations.

Superchannels

As mentioned, WDM networks currently transmit each 10G, 40G, and 100G optical signal as a single optical carrier that fits within a standard 50-GHz channel. At higher data rates, including 400G and 1T, the signals will be transmitted over multiple subcarrier channels (see Figure 2). The group of subcarrier wavelengths is commonly referred to as a "superchannel." Although composed of individual subcarriers, each 400G superchannel is provisioned, transmitted, and switched across the network as a single entity or block.

FIGURE 2. 400G modulation options and superchannels.

While 400G standards are still in preliminary definition stage, two modulation techniques are emerging as the most likely candidates: dual polarization quadrature phase-shift keying (DP-QPSK) using four subcarriers and DP-16 quadrature amplitude modulation (QAM) with two subcarriers. Due to the differences in optical signal-to-noise-ratio requirements, each modulation type is optimized for different network applications. The 4×100G DP-QPSK approach is better suited to long-haul networks because of its superior optical reach, while the 2×200G DP-16QAM method is ideal for metro distances.
Since 400G signals are treated as a single superchannel or block, the 400G signals shown in Figure 3 require 150-GHz- and 75-GHz- channel sizes, respectively. It's this transition to higher data rates that leads to the requirement for and adoption of new flexible grid channel assignments to accommodate mixed 100G, 400G, and 1T networks (see Figure 3).
A new flexible grid pattern has been defined and adopted by ITU G694.1. While commonly referred to as "gridless" channel spacing, in reality the newly defined flexible channel plan is actually based on a 12.5-GHz grid pattern. The new standard supports mixed channel sizes, in increments of n×12.5 GHz and easily accommodates existing 100G services (4×12.5 GHz = 50 GHz) and future 400G (12×12.5 GHz) and 1T optical rates.

FIGURE 3. Flexible grid channel plan.

One of the advantages of the flexible grid pattern is the improvement in spectral efficiency enabled by more closely matching the channel size with the signals being transported and by improved filtering that allows the subcarriers to be more closely squeezed together. As shown in Figure 5, four 100G subcarriers have been squeezed into 150-GHz spacing, as opposed to the 200 GHz (4×50 GHz) required if the subcarriers were transported as independent 50-GHz channels. The net effect of the flexible channel plan and closer subcarrier spacing is an improvement in network capacity of up to 30%.
One common "myth" in the industry is that legacy networks must be upgraded, or "flexible grid-ready," to support 400G optical rates and superchannels. While having flexible grid-capable ROADMs can improve spectral efficiency, they're not a requirement to support 400G or superchannels on a network. Since the subcarriers are fully tunable to any wavelength, they can simply be tuned to the existing 50-GHz grid pattern, allowing full backward compatibility with existing ROADM networks.

FIGURE 4. Transmitting 400G on legacy WDM networks.

CDC ROADMs

Closely associated with flexible grid channel spacing are colorless/directionless/gridless (CDG) and colorless/directionless/contentionless/gridless (CDCG) ROADM architectures. Along with gridless channel spacing, CDC ROADMs enable a great deal of flexibility at the optical layer.
Recall that existing ROADM systems are based on fixed 50-GHz-channel spacing and AWG mux/demux technology. The mux/demux combines and separates individual wavelengths into different physical input and output ports. While the transponder and muxponder themselves are full-band tunable and can be provisioned to any transmit wavelength, they must be connected to a specific port on the mux/demux unit. A transponder connected to the west mux/demux only supports services connected in the west direction. To reassign wavelengths – either to new channels or to reroute them to a different direction – requires technician involvement to physically unplug the transponder from one port on the mux/demux and plug it into a different physical mux/demux port.
CDC ROADMs enable much greater flexibility at the optical layer. The transponders may be connected to any add/drop port and can be routed to any degree or direction. Wavelength reassignment or rerouting can be implemented automatically from a network management system, or based on a network fault, without the need for manual technician involvement. The tradeoffs with CDC ROADMs are more complex architectures and costs.

Flexible Network Muscles

The existing 50-GHz-channel plan based on ITU G.694 has served the industry well for many years. But as the industry plans for the introduction of even faster 400G, and eventually 1T, optical interfaces, there's a need to adopt larger channel sizes and a more flexible WDM  spacing plan.
These higher-speed optical interfaces rely on a new technique involving superchannels that comprise multiple subcarrier wavelengths. These subcarriers are provisioned, transported, and switched across a network as a single block or entity. Flexible grid systems enable the larger channel sizes required by 400G and 1T interfaces, but also allow the channel size to be closely matched to the signal being transported to optimize spectral efficiency.
No discussion of gridless ROADMs would be complete without including new next generation CDC ROADM architectures. These new ROADMs will enable a great deal more flexibility and efficiency at the optical layer.
 

More bandwidth means more testing?

The use of MPO cables for trunking 10-Gbps connections in the data center has steadily risen over the past 10 years. That trunking requires use of a cassette at the end of the MPO cables designed to accommodate legacy equipment connections. Now that 40-Gbps and 100-Gbps connections are coming on the market, a migration path has emerged: Remove the 10-Gbps cassette from the MPO cable and replace it with a bulkhead accommodating a 40-Gbps connection. Then it might be possible to remove that bulkhead and do a direct MPO connection for 100 Gbps at a later date.
The problem is that while this migration strategy is an efficient way to leverage the existing cabling, in comparison to 10-Gbps connections, the 40-Gbps and 100-Gbps standards call for different optical technology (parallel optics) and tighter loss parameters.

In short, each time you migrate you need to verify the links to ensure the performance delivery the organization requires.

To understand the challenges ofMPO cables validation, it’s necessary to understand MPO cables and how they’re tested in the field. An MPO connection is about the size of a fingernail and contains 12 optical fibers, each less than the diameter of a human hair – and each one needs to be tested separately. That traditionally means the use of a fan-out cord to isolate each fiber, followed by tedious manual testing, tracing, and error-prone calculations.

The actual fiber test is quick enough: typically under 10 seconds per fiber once you’re in process. But you better be cruising: While one of our enterprise customers has data centers with as little as 24 MPO cables  trunks (x12 fibers each), that same customer also has a 30,000-MPO data center installation. That’s 30,000 connections with 12 fibers each, or roughly 3,120 hours in labor (and $343,200 in cost) if you had to test them all individually.

And at some point, you better have tested them. There were two primary drivers behind development of MPO cables trunks. The first was the ever-increasing need for cabling density in the data center. Cabling blocks airflow, so the denser the cable, the better the thermal management. And, as data center bandwidth steadily climbs to 10, 40, and 100Gbps, a dense multi-fiber cable becomes the only option.
But the second, perhaps more important factor, is the difficult and highly technical nature of field termination for fiber. We’re talking curing ovens, adhesives, microscopic fibers, etc. Given that expensive and time-consuming “craft” process, modular factory-terminated MPO cables promise simplicity, lower cost, and true plug-and-play fiber connectivity.

The challenge is that pre-terminated fiber is only guaranteed “good” as it exists in the manufacturer’s factory. It must then be transported, stored, and later bent and pulled during installation in the data center. All kinds of performance uncertainties are introduced before fiber cables are deployed. Proper testing of pre-terminated cables after installation is the only way to guarantee performance in a live application. In short, investing in factory-terminated fiber trunks to save time and decrease labor costs doesn’t really offer an advantage if the testing becomes an expensive bottleneck.
Testing and determining fiber polarity is another challenge. The simple purpose of any polarity scheme is to provide a continuous connection from the link’s transmitter to the link’s receiver. For array connectors, TIA-568-C.0 defines three methods to accomplish this: Methods A, B, and C. Deployment mistakes are common because these methods require a combination of patch cords with different polarity types.


You can buy fiber optic jumpers with any connectors from Optoroute.

How to test MPO/MTP Cable?

To understand the challenges of MPO cable validation, it’s necessary to understand MPO cableand how they’re tested in the field. An MPO connection is about the size of a fingernail and contains 12 optical fibers, each less than the diameter of a human hair – and each one needs to be tested separately. That traditionally means the use of a fan-out cord to isolate each fiber, followed by tedious manual testing, tracing, and error-prone calculations.

Testing and determining fiber polarity is another challenge. The simple purpose of any polarity scheme is to provide a continuous connection from the link’s transmitter to the link’s receiver. For array connectors, TIA-568-C.0 defines three methods to accomplish this: Methods A, B, and C. Deployment mistakes are common because these methods require a combination of patch cords with different polarity types.

So what would a proper MPO cable test look like? The answer is simple: Test all 12 fibers – the whole cable – simultaneously and comprehensively (including loss, polarity, etc.). That sort of test capability changes the fiber landscape, enabling installers and technicians to efficiently validate and troubleshoot fiber – flying through the process by tackling an entire 12-fiber cable trunk with the push of a button.

The tools to perform this type of test are just emerging on the market, and promise to reduce the time and labor costs up to 95% over individual fiber tests (according to internal research based on the average list of standard competitive products). Characteristics to look for in such a tool include:
An onboard MPO connector to eliminate the complexity and manual calculations associated with a fan-out cord.
A single “Scan All” test function that delivers visual verification via an intuitive user interface for all 12 MPO fibers in a connector.
Built-in polarity verification for end-to-end connectivity of MPO trunk cables.
“Select Individual Fiber” function that enables the user to troubleshoot a single fiber with more precision.
Demand for fast and reliable delivery of critical applications is driving data center technology to evolve at an ever-increasing pace. And that insatiable need for bandwidth ensures that the integrity of the data center has become inextricably linked to the strength of the fiber cabling infrastructure. The growing use of MPO fiber trunks – and the migration from 10-Gbps to 40/100-Gbps connections – means that it’s time to stop the cumbersome verification of individual fibers. After all, it’s a single MPO connection. You should be able to test it as one.
You can buy fiber optic jumpers with mpo/mpo connectors  from Optoroute now!

What is ROADM?

 

Transmode's ROADM units are a powerful part of the TM-Series enabling cost optimized Flexible Optical Networks based on DWDM technology. Built for dynamic network applications, the ROADM units allow hitless wavelength allocation and future proof traffic design.

Key benefits with Transmode's ROADM units are:

• Multiple use - can be used in bus and ring topologies as well as three- to eight-way mesh nodes with local add-drop
• Available as 2, 4 and 8 individual drop ports providing cost efficient alternatives in both access and metro networks
• Supports cutting edge ROADM node configurations such as colorless, directionless and contentionless nodes, allowing flexible and cost optimized handling of traffic
• Provides add/drop of any wavelength from/to any port, giving maximum flexibility in wavelength allocation
• Built-in Variable Optical Attenuator (VOA) for easier channel power balancing
• Compact design, giving small footprint
• Fully integrated with TM-Series and Transmode Network Manager (TNM)
• Low Power Design and small footprint ensures low total cost of ownership

The 1x2, 1x4 and 1x8 ROADM units are compact solutions for all network topologies. They are fully supported as units in the TM-3000 chassis and work as building blocks for reconfigurable add-drop nodes in up to 8 dimensions.

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

DWDM Play a significant Role in long-haul optical networks

Dense Wavelength Division Multiplexing (DWDM) is the technology of choice for transporting extremely large amounts of data traffic over metro or long distances in telecom networks. Optical networking and especially the use of DWDM technology has proven to be the optimal way of combining cost efficient transport with advanced functionality, which can cope with the bandwidth explosion from the access network.

DWDM typically has the capability to transport up to 80 channels (wavelengths) in what is known as the Conventional band or C band spectrum, with all 80 channels in the 1550 nm region. DWDM takes advantage of the operating window of the Erbium Doped Fibre Amplifier (EDFA) to amplify the optical channels and extend the operating range of the system to over 1500 kilometers. This denser channel spacing requires tighter control of the wavelengths and therefore cooled lasers as opposed to Coarse Wavelength Division Multiplexing (CWDM) which has broader channel spacing un-cooled lasers.
Transmode uses both DWDM and CWDM technologies as a way of transporting different types of services, e.g. Ethernet, SDH/SONET, and Fibre Channel (FC) for solutions in metro access to regional backhaul networks. DWDM is the variant of WDM technology that provides more functionality in terms of supported distance (for Transmode up to 1500+ km), number of wavelengths and dynamic behavior using ROADM technology.
Both Transmode's TM-Series and TS-Series areDWDM and CWDM agnostic. This means a CWDM network can initially be deployed with either product series, and when required, the network can be simply upgraded to a hybrid CWDM/DWDM network using common cards and pluggable optics. Therefore, by deploying Transmode'sDWDMor CWDM based solutions the lowest possible day 1 cost are enabled without sacrificing the scalability of the network.

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

What Contributions Active Optical Cables Have made to our High Speed Time?

There is no question that we live in a high-speed world. Our environment is shaped by places that pride themselves on services that emphasize quality, but prioritize speed. From fast food to the way we walk from one place to another, and even how we search for and obtain information, everything is seemingly done as quickly as possible. As technology has caught up to the speeds that at one point were merely desired but are now required, we have seen that to meet this demand you need to have the appropriate software and hardware.

So what are active optical cables – and, more importantly, why should you care? Let’s start with the basic definition that you would stumble upon if you happen to plug the term into a search engine: A specialized optical cable that uses electrical-to-optical conversion on the cable ends to improve speed and distance performance of the cable without sacrificing compatibility with standard electrical interfaces.

As for the second point, “why should you care?” Well, put simply, active optical cabling is one of the fastest growing technologies in the data center space. As people expect more information to be available at their fingertips, our communications systems will need to be quicker – and active optical cables is one of the best solutions to this challenge.

So what do active optical cables specifically bring to the table and why are they the way to go? There are a few things that these cables bring to the table that can have an immediate impact on your network.

Primarily, these cables offer both higher bandwidth and a longer reach with a better footprint than current copper cables. When compared to the incumbent copper cables in most cases, active optical cables provide lighter weight, a smaller size, EMI immunity, a lower interconnection loss, and reduced power requirements. It almost seems too good to be true, but active optical cables are one of those technological innovations that make their predecessors look obsolete and unsophisticated.

Another element driving the growth of active optical cables use is the expansion of data centers. We are seeing far more “mega datacenters” being constructed, which means the cables connecting the infrastructure must go further than traditionally expected. The other data center trend that is accelerating the active optical cable market is the creation and development of new mid-level servers and switches that are optimized for these cables. Developments such as these have accelerated and legitimized the development and deployment of more cost-effective QSFP+ 40-Gbps optical transceivers – including their use and acceptance as interfaces for active optical cables this year and beyond.

In closing, let’s look at the numbers. For that is how many responsible decisions must be made every day - especially in the business world. According to the market research and analysis firm Optoroute, in 2012 the active optical cables market grew by a staggering 65%, much greater than their forecast. They are now predicting that the active optical cabling market will grow 30% to $150 million this year. This increase is in large part due to datacenter managers planning for the future and the growth of the Infiniband market.

For more active optical cables products, please visit http://www.optoroute.com.cn/

Optoroute Networks extends the 10x10 MSA to 80km

Optoroute has demonstrated a 100 Gigabit CFP module with an 80km reach; a claimed industry first. The company has also developed the Qbox, a 1 rack unit (1RU) extended reach platform capable of 400-800 Gigabit-per-second (Gbps) with a reach of 80-200km.

 

Optoroute's CFP does not require the use of external DWDM multiplexing/ demultiplexing and can be added directly onto a router. Source: Effdon Networks Available 100 Gigabit CFP module have so far achieved 10km. Now with the Effdon module a 80km reach has been demonstrated that uses 10Gbps optics and no specialist silicon.

Optoroute's  design is based on the 10x10 MSA (multi-source agreement). "We have managed to resolve the technology barriers - using several techniques - to get to 80km,"

 

There is no 100 Gigabit standard for 80km. The IEEE has two 100 Gigabit standards: the 10km long reach 100GBASE-LR4 and the 40km extended reach 100GBASE-ER4.

Meanwhile, the 100 Gigabit 10x10 MSA based on arrays of 10, 10 Gigabit lasers and detectors, has three defined reaches: 2km, 10km and 40km. At the recent OFC/NFOEC exhibition, Oplink Communication and hybrid integration specialist, Kaiam, showed the 10x10 MSA CFP achieving 40km.

Optoroute has not detailed how it has achieved 80km but says its designers have a systems background. "All the software that you need for managing wavelength-division multiplexing (WDM) systems is in our device," says Efron. "Basically we have built a system in a module." 

These system elements include component expertise and algorithmic know-how. "Algorithms and software; this is the main IP of the company," . "We are using 40km components and we are getting 80km."

 

100 Gigabit landscape 

Optoroute says that while there are alternative designs for 100 Gigabit transmission at 80km or more, each has challenges.

A 100Gbps coherent design achieves far greater reaches but is costly and requires a digital signal processor (DSP) receiver ASIC that consumes tens of watts. No coherent design has yet been implemented using a pluggable module.

Alternative CFP-based 100Gbps direct-detection designs based on a 4x28Gbps architecture exist. But their 28Gbps lanes experience greater dispersion that make achieving 80km a challenge.

MultiPhy's MP1100Q DSP chip counters dispersion. The chip used in a  CFP module achieves a 55km point-to-point reach using on-off keying and 800km for dense WDM metro networks using duo-binary modulation.

But Optoroute points out that its point-to-point CFP achieves 80km without using an external DWDM multiplexer and demultiplexer - the multiplexing/demultiplexing of the wavelengths is done within the CFP- or external amplification and dispersion compensation. As a result, the CFP plugs straight into IP routers and data centre switches.

"What they [data centre managers] want is what they have today at 10 Gig: ZR [80km] optical transceivers," says Efron

 

 

Reach extension

Optoroute Networks' Qbox platform provides data centre managers with 400-800Gbps capacity while offering a reach up to 200km. The box is used with data centre equipment that support CXP or QSFP modules but not the CFP.  The 1RU box thus takes interfaces with a reach of several tens of meters to deliver extended transmission.

Qbox supports eight client-side ports - either 40 or 100 Gbps - and four line-facing ports at speeds of 100Gbps or 200Gbps for a reach of 80 to 200km. In future, the platform will deliver 400Gbps line speeds, says Efron.

Samples of the 80km CFP and Qbox are available for selected customers, while general availability of the products will start in the fourth quarter of 2013. 

 

 

How to Publicize Your Website

E-commerce is getting more and more popular. The rapid expansion and development has posed great threat to traditional business. The past ten years witness a boom of Chinese E-commerce. In Particular, some Chinese local e-commerce operators such as Taobao, JD, Dangdang, Tmall almost occupy the majority of market share. Their success is never a sheer coincidence but co-efforts of all staffs.

E-commerce, in short, is doing business online. Namely, website is just like your store, which is crucial to people's fist impression. That's why E-commerce operators always pay much attention to improving their website. A user-friendly, clear and featured website can easily catch visitors' eyeballs. Thus, step one, set up a stylish and practical website. Then, how to publicize your website should be put on the top agenda, which directly influences whether you can successfully get your website across and exposed to the public. Of course, there are many channels to publicize your website. For example, free channels such as social network, forum, blog and other payable channels such as online ads, exhibition, etc.

Now we have successfully established our website (http://www.optoroute.com.cn/) but my problem is how to effectively publicize our website. In my opinion, online marketing is a long process. It takes longer time to get your efforts paid off. Now I just ask your experts for help. Could you please give me some advices or share your experience. Your precious ideas and suggestions will be highly appreciated. Thanks so much.

You can send E-mail to my mailbox: Melissa@optoroute.com.cn

Our website http://www.optoroute.com.cn/. Also our blog http://optoroute.blogspot.com/

Any suggestions, feel free to tell me. Thanks again.

 

Complex coding concepts for increased optical bit transfer efficiency

In the first article of this series,we found that more efficient techniques than on/off keying (OOK) for transferring bits over the existing fiber infrastructure must be employed to meet the challenges of the cloud revolution and the resulting data avalanche. WDM, for example, has been used very successfully to increase the number of bits transferred over a single fiber; now polarization-division multiplexing (PDM) is being added to double the capacity as well. Both strategies have in common that on each channel or in each polarization plane, only one bit is encoded with a state of the signal, representing a “symbol.”

This is where complex transmission comes into the game and demonstrates its huge potential. Instead of transmitting a binary data stream, several bits can be coded to a new symbol, and a stream of these symbols can then be transmitted. Figure 1 illustrates this for 2 bits being coded to one new symbol. In this way, twice the amount of data can be accommodated in the same bandwidth.

Figure 1. Coding concept: Use of symbols to represent a series of bits, where 2 bits are represented by one alphabetic symbol.

Of course, with this knowledge one can imagine schemes where a much larger number of bits are defined by a single symbol that enables a data rate many times greater than in OOK, where a series of ones and zeroes is transmitted.

How does this happen in practice?

In OOK, the approach is basically that when the laser source is turned on, this is interpreted as a “one,” and when it is turned off, this reflects a “zero.” In other terms, when the light amplitude exceeds a certain level, this is a one, and a zero is when the amplitude falls below this level.

But as a light wave is defined by more parameters than just amplitude, we also have more possibilities to encode information by using all of the light wave’s degrees of freedom. Figure 2 shows the mathematical description of the electric field of an electromagnetic wave with two polarization components E_x and E_y. These orthogonal components are used in PDM as two different channels to transfer independent signals. In WDM, different frequencies ω are applied as different channels for independent data transfer at these frequencies/wavelengths. For complex modulation schemes now, additionally to the amplitude E, the phase Ф of a light wave is modulated for defining the above described symbols.

Figure 2. Mathematical description of an electromagnetic wave (electric field).

The electric field of the modulated light wave can also be described in the complex plane with an I/Q diagram. Here, I is the in-phase or real part and Q the quadrature or imaginary part as shown in Figure 3 (after removal of time and space dependency of the wave and for one polarization plane only). A symbol corresponds to a point (also called a “constellation point”) in this diagram (which itself also is referred to as a “constellation diagram”) and is defined by a Q and an I value or in polar coordinates by amplitude E and phase Ф. The constellation points correspond to the symbol clock times and are also called “detection decision points.”

Figure 3. I/Q representation of a symbol.

Figure 4 shows the constellation points for the four symbols in quadrature phase-shift keying (QPSK), a complex modulation type where the four symbols encode 2 bits each. The constellation points are situated on a circle with radius E. This means that the symbols only differ in phase (always π/2 between the neighboring points), not in amplitude. In the time domain, the four symbols are reflected by a combination of two waves of the same amplitude and different phase.

Figure 4. Four symbols/constellation points for 2 bits encoded in one symbol (here quadrature phase shift keying, or QPSK).

Conventional OOK can also be represented by a constellation diagram. As information is in amplitude only, the bit value 1 can be anywhere on a circle with radius (= amplitude) E (see Figure 5).

Figure 5. Constellation diagram of QPSK modulation versus OOK; in OOK phase is random.

We mentioned that you can think out plenty of schemes where many more bits are encoded in one symbol, and of course different ways to implement this as well. Figure 6 shows only a selection of possible coding schemes.

Figure 6. Constellation diagrams of a selection of possible coding schemes.

 For more details on the coding concepts, please visit http://www.optoroute.com.cn/

Optoroute offers 40G TOSA and ROSA

Optical component and subsystem developer Optoroute Technologies has unveiled a line of transmit optical subassembly (TOSA) and receive optical subassembly (ROSA) components for CFP and QSFP+ optical transceiver applications.

Optoroute says it is shipping TOSAs and ROSAs in 8x10G and 10x10G configurations that are compliant with the CFP MSA. Meanwhile, additional components for 4x10G, 4x25G, and 8x25G transceiver applications should be available “in the coming quarters,” the company adds.

The new TOSAs and ROSAs will play in QSFP+, CFP, and CFP2 modules for data center communications. The TOSA/ROSA designs use Optoroute's proprietary low-loss silica-on-silicon planar lightwave circuit (PLC) technology and hybrid integration techniques to create compact photonic integrated circuits (PICs).

The company says the new TOSA and ROSA products are emblematic of  Optoroute’s refocus on component and subsystem supply after an unsuccessful expansion into systems development put the company on the brink of bankruptcy. Management says a financial restructuring has given Optoroute a clean balance sheet with money left over for production expansion and new product development – and, hopefully, restored customer confidence.

For More product information, please visit our website http://www.optoroute.com.cn/

Active/Passive Optical Modules and Cables: Optoroute Five Types Of Quad Small Form-Factor Plu...

Active/Passive Optical Modules and Cables: Optoroute Five Types Of Quad Small Form-Factor Plu...: QSFP+ (Quad Small Form-Factor Pluggable Plus) cables provide a high density, high bandwidth, cost effective solution for a variety of markets and applications including switches, routers, HBA’s, high performance computing and mass storage sub-systems by manufacturers’ such as IBM, Cisco, qLogic, etc. QSFP+ cables are designed for data rates up to 40Gb/s supporting Fibre Channel, Ethernet, SDH/SONET and Infiniband standards. Optoroute provides a wide variety of 40G QSFP+ Cables, including 40G QSFP+ Active Copper Cables, 40G QSFP+ Passive Copper Cables, 40G QSFP+ AOC Cables, QSFP+ to 4 SFP+ Breakout Cables, 120G CXP Active Optical Cable, with different lengths and wire gauges. Optoroute also offers OEM and ODM service according to customers’ specific requirements.

40G QSFP+ Active Copper Cables

QSFP+ (Quad Small Form-factor Pluggable Plus) Active Copper Cables are suitable for very short distances and offer a highly cost-effective way to establish a 40-Gigabit link between QSFP+ ports of QSFP+ switches within racks and across adjacent racks. The QSFP+ cable assemblies are high performance, cost effective I/O solutions for LAN,HPC and SAN. The high speed cable assemblies meet and exceed Gigabit Ethernet, InfiniBand and Fiber Channel commercial temperature requirements for performance and reliability. The cables are compliant with InfiniBand Architecture, SFF-8436 specifications and provide connectivity between devices using QSFP ports. We now provide several lengths to accommodate your installation requirements, welcome to buy it from Optoroute. We offer the 40G QSFP+ copper cables with different length ranging from 0.5m to over 20m.

40G QSFP+ Passive Copper Cables

The QSFP+ passive cable assemblies are high performance，cost effective I/O solutions for 40G LAN, HPC and SAN applications. The QSFP+ passive copper cables are compliant with SFF-8436, QSFP+ MSA and IEEE P802.3ba 40GBASE-CR4.  It is offer a low power consumption，short reach interconnect applications. The cable each lane is capable of transmitting data at rates up to 10Gb/s, providing an aggregated rate of 40Gb/s. We now provide several lengths to accommodate your installation requirements, welcome to buy it from Optoroute. We offer the 40G QSFP+ copper cables with different length ranging from 0.5m to over 20m.

40G QSFP+ AOC Cables

QSFP+ Active Optical Cable (AOC) is a high performance, low power consumption integrated cable for short-range multi-lane data communication and interconnect applications, supporting 40G Ethernet, fiber channel and PCIE. It is compliant with the QSFP MSA and IEEE P802.3ba 40GBASE-SR4. It integrates four data lanes in each direction with 40 Gb/s aggregate bandwidth. Each lane is capable of transmitting data at rates up to 10Gb/s with lengths ranging from one to 100 m. Optoroute QSFP AOC is an assembly of 4 full-duplex lanes, where each lane is capable of transmitting data at rates up to 10Gb/s, providing an aggregated rate of 40Gb/s. We now provide several lengths to accommodate your installation requirements, welcome to buy it from Optoroute.

QSFP+ to 4 SFP+ Breakout Cables

QSFP+ to 4 SFP+ hybrid splitter cables make a great cost-effective interconnect solution to IT professionals by providing much needed space for data centers and cost cuts. These cables allow you to connect your QSFP+ and SFP+ Switches and Network cards without upgrading your entire data center or storage array. They can be used for QDR infiniBand, 40 Gigabit Ethernet and 10Gigabit applications. For typical applications, users can install this splitter Active Optical cable between an available QSFP port on their 40Gbps rated switch and feed up to four upstream 10GbE-SFP+ enabled switches. Each QSFP-SFP+ splitter Active Optical cable features a single QSFP connector (SFF-8436) rated for 40Gbps on one end and (4) SFP+ connectors (SFF-8431), each rated for 10-Gb/s, on the other. Optoroute QSFP to 4x SFP+ breakout Active Optical Cable offers IT professionals a cost-effective interconnect solution for merging 40G QSFP and 10G SFP+ enabled host adapters, switches and servers, welcome to buy it from Optoroute.

120G CXP Active Optical Cable

CXP-active optic cables are a high performance, low power consumption, long reach interconnect solution supporting 120G Ethernet, fiber channel and PCIe. It is compliant with the 120Gbits Small Form factor Hot-Pluggable CXP-interface. Optoroute CXP AOC is an assembly of 12 full-duplex lanes, where each lane is capable of transmitting data at rates up to 10Gb/s, providing an aggregated rate of 120Gb/s. Welcome to visit Optoroute website for more information.

Optoroute is a professional fiber optic products supplier and manufacturer. We provide a wide variety of fiber optic products, we not only have the 40G QSFP+ Cables, but also have other types Direct Attach Cables. If you can’t find what you need from us, don’t worry, just contact our sales who will offer instant help to you. Beisdes, both customized order and OEM service are available in Optoroute. Welcome to Optoroute, I’m sure this is your idea destination.