Using CWDM Technology To Construct Cost-Effective Fiber Networks

The utilization of fiber optic cables for communication has opened up gates for communication multiplexing technologies that increase the capabilities at minimum costs. Coarse wavelength division multiplexing (CWDM) modulates different wavelength laser beams with multiple signals. Essentially, what this means is maximized utilization of a single fiber optic to deliver and get a large number of signals, minimizing costs for telecom companies. Companies simply employ the right optical amplifiers, multiplexers and demultiplexers to boost capacity from the fiber optic using CWDM technology.

In CWDM technology, it comes with an increase in channel space. This means requirement of less sophisticated and less costly transceiver devices. Operating in the same window of 1550 nm and making use of OH-free silica fibers, maximum efficiencies are achieved in channels 31, 49, 51, 53, 55, 57, 59 and 61. The channels are spaced 20 nm apart. DWDM spaces them 0.4 nm apart. Less precision optics minimizing cost, uncooled lasers with lower maintenance requirements can therefore be used in CWDM devices, operating in the region of 1470, 1490, 1510, 1530, 1550, 1570, 1590 and 1660nm. 18 different channels can be used with wavelengths as much as 1270 nm. For instance, a 8 channel CWDM includes 8 different CWDM channels. In addition to being economical, power consumption for laser devices used in CWDM technology is also far less.

CWDM signals cannot be transmitted long term but are ideal for applications inside a range of 60 km for example in a city as well as for cable tv networks allowing upstream and downstream signals. CWDM product is usually considered a low-cost alternative which is now widely used to replace the DWDM system. Due to the benefit of CWDM technology uses low cost lasers that don't need cooling and low-cost passive filter. Moreover, if using CWDM technology, we can use low-cost and smaller transceivers such as CWDM 10Gig SFP+. However, because of relatively large CWDM channel spacing, so the system will reduce the number of available wavelengths, this also limits the system's transmission capacity.

Related technologies are dense wavelength division multiplexing (DWDM) and conventional WDM. Conventional WDM use the 3rd transmission window with a wavelength of 1550nm, accommodating as much as 8 channels. DWDM is identical however with a higher density channel. Systems could use 40 channels, each at 100 GHz spacing or 80 channels spaced 50 GHz apart. A technology, the ultra dense WDM is capable of doing working in a spacing of just 12.5 GHz, allowing more channels. However, DWDM and WDM are much more expensive in contrast to CWDM.

A quantity of manufacturers offer all related CWDM multiplexer, demultiplexer and optical amplifier. Networking solution providers would be the right individuals to seek guidance for use of CWDM, DWDM or WDM technology. They perform entire installation and commissioning from the right, integrated devices for error-free high speed, high data transmissions over fiber optic cables. Cost and gratifaction optimized CWDM solutions with built-in expansion capabilities can be found from reliable and trusted online network solution companies. Choose the best one with years of experience and technological expertise to provide the best CWDM solution and use the CWDM technology to construct your cost-effective fiber optic networks.

Fiber Optic Internet Services

Fiber Optic Internet is among the modern channel and way of communication. It’s greatly improved the method people manage businesses. This marvelous approach to communication that uses light in glass tubes was initially used in the 1970s by a great scientist and engineer. With the use of this cable, data transmission is made possible through sending information with the cable with the pulsing light.

There are various beneficial packs that include fiber optic internet. Probably the most distinctive characteristic is its speed. It’s incredibly fast that anybody who uses the service will enjoy the comfort of speedy internet service- especially when one is rushing an important task such as a portfolio or school project. Download files or submit files; buy online; download music; watch a film and many more- the fiber optic internet may be the way to go.

With the short speed, employees and executive officers can run their tasks at double or triple but a fraction of time. Less time is required for awaiting a file to load and therefore fiber optic internet increases workplace productivity. Along with the high-speed and also the rise in production rates, almost all businesses will prosper. More production plus more work equals more profit. No stone remains untouched. Every employee beginning with the cheapest categories climbing as much as the highest rank is going to be taken advantage of this fast fiber optic online sites.

The fiber optic internet has been a good steer and active cause of sustainable development and growth through dissemination of information out of all sectors from the economy. It has ensured that expansions are achieved even in the telephone signaling and cabling of televisions.

Subscription to a fiber optic online sites, every businessman or manager or boss will be amazed about how an employee does his job at a considerably faster rate rather than using a dial-up connection which takes forever to complete tasks. Employees will have the convenience of using such high speed internet service and it will also improve the way they intend to accomplish their individual tasks. Every person in the office is motivated to operate and submit their reports and files on time or well in advanced because of this very handy technology.
Clients could be more than pleased with the short and efficient service a business gives to them due to the help of a Fiber Internet connection. It starts from the benefits of this particular service and falls to motivating the workforce after which bringing on more client satisfaction. The services are particularly useful when you need to accomplish a report with your an earlier deadline. Fast internet service equals rapid results.

A lot of businesses are reaping the rewards that a fiber optic internet connection gives for them. They not only retain and develop their valued clients they also gain a new customer base. More customers result to more profits and more business. No one would want to avail of a sloppy service which in turn delivers disappointing results. Everyone wants to obtain their concerns and requests addressed right away which is why this sort of online sites is very beneficial not only to big and small businesses and industries, but additionally to university students and stay-at-home that do their very own daily tasks of reports, online investigation and paper works.

I am a specialist from FiberStore, where you can obtain the most quality fiber optic products, for example plastic optical fiber, MTP trunk cable and other fiber patch cables for the fiber optic internet services.

The Application of 10G PON Technology

With the major carriers "Broadband speed", "Light of Copper" project extensively, The future will be a multimedia broadband services, video on demand, interactive games as the main feature, high-bandwidth, integrated operators will be judged promoted by the merits of the standard broadband products.

Under the broadband Fiber Optic Network in the trend, PON technology has become the world's attention to various telecom operators hot technology is one of the operators to implement "broadband speed", "Light of Copper" engineering technology base. Wheter EPON, or GPON, which provides only for the uplink and downlink bandwidth of 1G or 2G, but with the current interactive network TV (IPTV), high definition television (HDTV), online games, video services and other large flow, a large broadband business development and popularization of the per-user bandwidth demand is expected to grow every three years, a trend of increasing magnitude, from the future operator of long-term trends, per-user bandwidth demand will be 50-100 Mbit/s between. This way, EPON and GPON are unable to meet the future needs of the development of broadband services, the existing PON port bandwidth, there will be a bottleneck. Therefore, ITU-T, FSAN, IEEE and other major standards organizations begin the next generation of PON technology research.

Similar to 1G PON Technology, 10G PON and 10G EPON technology is still divided into two camps 10G GPON. In IEEE 802.3av 10G EPON standards, maximizing follows the usual IEEE 802.3ah content, with good upward compatibility.

>> 10G PON technical analysis

Recalling the history of PON technology can be found in each of the PON technology from birth to the end of the day have to go through large-scale commercial development of technical standards, the relevant chip and optical module development, test and production, the creation of experimental and commercial bureau 4 stages of deployment, which lasted five years or so, each one of which will go through several stages of development of the argument.

* Standardization Advances

Standards are mature is the precondition of judging whether a technology have lead to condition. At this stage, including IEEE, ITU-T, FSAN and number of ongoing international standardization organizations 10G EPON and 10G GPON standards development work of two technologies. Overall, the 10G EPON technology start time earlier than 10G GPON, therefore, the current standardization process of 10G EPON slightly faster than 10G GPON.

a. 10G EPON

Technologies with 1G EPON, 10G EPON standards are mainly led by the IEEE to complete. IEEE organization at September 12, 2009 released the 10G EPON international standards 802.3av, this standard focuses on the physical layer 10G EPON technology research, followed the tradition of 1G EPON MPCP protocol, the 1G EPON downlink bandwidth increases to 10G at the same time, to ensure that the operator of the original investment is not compromised and 10G EPON smooth upgrade, IEEE 802.3av standard defines and 1G EPON ONU coexist in the same ODN network of 10G EPON ONU standard parameters.

Further, in IEEE 802.3av standard, the physical layer defines two parameters: one asymmetric model, which 10G rate downlink and 1G rate uplink; other is symmetrical pattern, i.e. uplink rate and downlink rate are both 10G. Asymmetric mode can be considered as a transitional form symmetrical patterns, in the early less demand for upstream bandwidth and cost sensitive applications, you can use an asymmetric form. With the development of business and technology progress, will be gradually transition to a symmetrical mode.

b. 10G GPON

According to ITU-T Study plans, NGPON will experience two standard phases: the first phase is the coexistence with GPON, GPON ODN heavy use of XG-PON, which in turn contains the uplink and downlink phase XG-PON1 asymmetric and symmetric XG-PON2 two kind of model; Second stage is completely new ODN's NGA2. High concern Wavelength Division Multiplexing - Passive Optical Network (WDM-PON) technology areas belong to the second stage, it was adopted in a fiber access network using multiple wavelengths to achieve the expansion, but the burst mode CWDM, colorless ONU transceivers, tunable WDM devices and some difficult technology can not break, WDM-PON is still at the proof stage.

In the end of September 2009 meeting of the ITU-T SG 15 plenary session, Q2 Working Group officially launched the NG-PON standard text in the first stage, that overall demand for next-generation PON systems (G.987.1) and Physical Layer Specifications (G.987.2), and also developed in mid-2010, publishing transmission convergence layer (G.987.3) and management control interface (G.988) standards program.

* Technical Parameters

Wheter IEEE 802.3av, or ITU-T G.987 protocol suite, all relevant technical parameters for 10G PON physical layer index, optical power budget to make a detailed definition. However, due to the two major standards organizations considered the starting point, the technical indicators are also some differences.

a. 10G EPON

There are four key points of 10G EPON technology:

1. Defines six 10G EPON optical power budget, in view of the asymmetric mode PRX10, PRX20 and PRX30 as well as for symmetric mode PR10, PR20 and PR30, these six kinds of optical power budget model is basically to meet the construction needs of the service provider network;

2. 10G EPON technology in achieving the 1G EPON conventional multi-point control protocol layer (MPCP) based on the forward compatibility, also extended the original message type, for reporting optical terminal equipment (OLT), ONU Optical Transceiver Module switch time to meet the 10G EPON system requirements;

3. 10G EPON uses (255, 223) Forward Error Correction (FEC) encoding method, the encoded with FEC coding for the same strain of 1G EPON, but its strong support 10G EPON coding gain can lower the sensitivity of the optical receiver;

4. 10G EPON uplink and downlink wavelength for the re-planning, downlink using 1268-1280nm wavelength, then reuse the original uplink of 1G EPON 1575-1580 nm wavelength, the wavelength in order to avoid conflicts, 10G EPON uplink only use time division multiple access (TDMA) manner.

b. 10G GPON

Has been released G.987.1 standard that defines 10G GPON system's overall technical requirements and system architecture, clearly put forward the 10G GPON system to ensure good QoS, based on the traditional telecom services to fully support all emerging businesses and the same time, also provides dynamic Bandwidth Allocation (DBA) algorithm, energy saving, authentication and encryption related content to inherit the original 1G GPON technology; The G.987.2 is the focus of standardized 10G GPON physical layer parameters, including downlink rate, ODN power budget, splitting ratio, up and down the line wavelength range and line coding, etc., although down the line of 10G EPON same wavelength range and 10G EPON, GPON but due to the wavelength with 1G is not conflict, therefore, 10G GPON uplink and downlink are used wavelength division multiple access (WDMA) manner.

* Industrial chain development

A complete industrial chain, including chip PON, optical modules and equipment three links. If to analysis PON industry chain, it need to start from the three links, analysis of every link current development status and future development trend.

Overall, 10G EPON and 10G GPON is currently not reach the requirements of large-scale commercial applications, although some equipment manufacturers have recently introduced a 10G EPON or 10G GPON products, and with operators, the creation of some experimental inning, but still in the laboratory testing phase, is still some distance away from the large-scale commercial.

>> Conclusion

10G PON technology to meet future access networks, "large-capacity, fewer offices," the direction of development, while improving access speed, supports larger branching ratio, covering more users. Therefore, 10G PON technology will become the future telecom operators to achieve "broadband speed", "Light of Copper" and other broadband network construction hot technology for sustainable development.

To Introduce Optical Communication and Internet Technology

Technology of terabit optic circuit packet integrated switching system

New exchange system and integrated optic circuit packet layers will be provided to meet the large capacity, high quality, low cost and effective demand so as to adapt to the cable wireless traffic spikes in the service in the future.

A connection-oriented packet transport technology is considered to be an effective way to improve the performance of packet data transmission. It is necessary, can put a layer of transport network in the direction of capital spending and minimizing operating costs to overcome the network provider's storage and traffic increase of income. And unified control mechanism is applied to the network resource allocation, flexible wavelength circuit and packet layer according to the service characteristics. The key technologies of the system are as followings.

• Technology of Terabit Optic-Circuit-Packet Integrated Switching System

  * Connection-oriented Packet Transport

  * Optic-Circuit-Packet Integrated Switch

  * Optic-Circuit-Packet Layer Integrated Control/Management

• Technology of beyond-100G Optical Transmission

  * Long-reach OTN Transceiver

  * Short-reach Ethernet Transceiver

Technology of terabit optic circuit packet integrated switching system

Smart IDC Network Control Technology for Cloud Service

Along with the rapid spreads and changes of cloud services and the technologic growth of the components in the IDC, the IDC networks are demanding following changes.

Cloud optimized: The virtualization rate of the server is rising up to 10:1-100:1 and storage virtualization is also possible recently. So IDC is requiring the cloud-optimized virtualization to the network side which are connecting the virtualized cloud resources.

Flattened: There are network control needs to reduce the delay latency of virtualized server-to-server communications which is occuping up to 70%, to rise the utilization rate the link resources of L2 IDC networks of Tree-shape multi-layer hierarchical architecture with STP.

Auto-Managed: There are demands of integrated management of network and cloud resources between IDC and create/delete/VM migration to ensure seamless services in the cloud.

Therefore, our research target to develop the Smart IDC fiber optic solution to solve the current problems of IDC network with the 3 IDC network control technologies of the Cloud-Optimized Virtual Network Control technology, the Flattened IDC Network Control Technology and Auto-managed IDC network control technology.

High speed optical transmission technology

The rapid progress in optical transmission technology has been supporting the ever increasing transmission traffic. In particular, the WDM technology, it is by the end of last century, played a main role. However, the new technology needs to use data traffic exponentially. A solution is 100Gb/s transmission. IEEE announced 40G/100G Ethernet standard and ITU-T has completed ONT standard to accommodate 100G signals in DWDM backbone network. Recently, the 100Gb/s transmission technology has become the commercial deployment, in addition to the existing 10Gb/s and 40Gb/s. Already technologies beyond 100G or 400G are started being discussed. With a long-term perspective, it is a disruptive

technology, SDM (space division multiplexing) technology is seriously explored to harness the traffic in economic and energy efficient way.

Next Generation WDM-PON Technology

The WDM-PON is promising technology to provide broadband access offering optic-wireless converged next generation multi-application service with the highest quality.

There are many advantages of the WDM-PON:

* Using multiple wavelength on a single fiber, each of which carries a transmission bandwidth up to 10Gb/s at maximum; Therefore, the WDM-PON can reduce the optical access infrastructure;

* Suitable for long-reach application and possible to achieve OPEX reduction;

* Provide co-existence with legacy TDM-PON (EPON system, and GPON) systems and pay as you grow upgradability;

* Unique advantages of so-called protocol transparency, which means that it requires no specific transmission protocol, and the physical layer security, in addition to scalability in the increase of the bandwidth and guarantee of the quality of service based on bandwidth abundance.

FiberStore Overseas Market Grew Rapidly

"Building an International leading manufacturer of optical devices is our strategic goal, while opening up overseas markets is one of the important parts" Andy Zhou, FiberStore product and market vice president disclose, in 2012 the company's revenue from overseas markets accounted for 27.6% of the total revenue, and the goals for the feature 3-5 years is to improve the proportion to 40%.
Good Growth in Overseas Markets
Andy Zhou discloses, 2012 FiberStore revenues from overseas markets have achieved 97 million $, increases 44.98% of the previous year, with gross profit margin of 25.86% which is higher than the national level.
FiberStore overseas sales with the own main channel, after years of layout, have comprehensive covered Europe, North America, Asia Pacific, Latin America markets, and has set up offices in Europe, North America and Japan, and its products solutions also enter dozens of countries.
Benefit from this, in recent years, even though the global economic turn down, FiberStore contract amount continually high record highs, especially in key markets such as Europe and North America, by cooperating with overseas large equipment supplier, the product promotion and the project has made big progress, Andy Zhou presented.
For example, he said that in the past year. FiberStore broke into the closed Japanese PON market supply system, and achieved a breakthrough, market segment in Europe also "Full Bloom", making the company the first choice for many integrators.
On the client side, FiberStore entered the top twenty global optical communication equipment enterprises in the world, and become the main supplier of fiber optic transceivers for the top five equipment companies.
About FiberStore
The FiberStore Co., Ltd. is China's largest optical component supplier, which is also the only company in China optoelectronic devices, systematic, strategic research and development of high-tech enterprises, and optoelectronic devices industry the most influential one of the entities.
For about more than 13 years development from 2000, FiberStore Co., Ltd has established an advanced research and development laboratories and production lines, including passive optical network, or PON, subsystems, optical transceivers used in the enterprise, access, and metropolitan segments of the market, as well as other optical components, modules, and subsystems. In particular, FiberStore products include optical subsystems used in fiber-to-the-premise, or FTTP, deployments which many telecommunication service providers are using to deliver video, voice, and data services.

Silicon Photonics Lead The Trend Of 100G Network

FiberStore news, when assembled eliminated pure handmade reliable optical components containing hundreds of optics, steering the occasion of silicon photonics technology, the industry will enter a new better world. On the other hand, switching network upgrade from 10G to 100G, even when eventually reach 1TB, will also face tough challenges from silicon photonics technology. Some optical function is easy to realize by silicon, but some are not. In fact, the entire optical engine must be integrated in silicon platform.
Optical engine can handle multiple high-speed electrical channels, converts it to optical signal, then together the information on these channels, through an fiber optic to transmit the information to any location ─ ─ distance from near to the next frame or as far as across the entire data center from the other end. At the receiving end, optical engine will flow received light streams separate into different channels, and then converted back to radio channel. In the data center, optical engine used for connecting the cluster switches and routers, which is a low power consumption, smallest pluggable transceiver technology; optical engine is also used in active optical cable to connect to the server and switch. In addition, the optical engine soon will also be embedded into the splint (mid-board) in order to reduce the consumption of board to board application and increase the density.
However, integrating optical functions on CMOS platform will encounter many challenges, which is original used to realize electric function design. Take a look at each key photoelectric function and the challenges of its fully integration in a CMOS platform.
Laser
Laser provides fiber optic light source for the optical engine, but to some data centers, using laser is too expensive. Kotura has developed chip function by using low-cost low-speed laser. Laser is a type of optical component which has not achieved single-chip integration, but the latest development of laser and array of flip chip bonding technology, have made it into a large number of low-cost manufacturing process. Chip functions removed the lens, isolator and beam collimator needed by traditional laser subassembly. The design of Kotura laser removed the expensive sealed package. In the automated assembly platform, just a few seconds for the array laser entire fabric and welded to silicon photonic chip, but also overcome the difficult problem of low-cost light source integrated in the chip.
The real value of fiber optic network is the ability to combine multiple wavelengths of light into one entity channel. To the 100G interconnection,the use of this called wavelength division multiplexing (WDM) parallelism, put the light combination of four wavelengths in a fiber. Of course, the four parallel fiber channel can work, but this increases the cost of network, but also a waste of bandwidth of fiber optic. WDM makes the use of same data center architecture to expend become possible, in order to support more channels in the future.
Because WDM requires both specific wavelength and multiplex wavelength laser, and therefore using silicon photonics to achieve is not easy. Nevertheless, the industry still don't want to use the expensive specific wavelength laser, which is commonly used in telecommunications network. A better solution is to use a universal laser, through integration of optical switch reflector in the silicon chip changes universal laser into specific wavelength laser. By changing the position of the reflector, Kotura will make each gain chip becoming a unique specific wavelength laser.

Fiber optic network has become the protagonist

The most of today’s telecommunication systems is run on a fiber optic network. This has been largely due to the fact that such networks are perfect for transferring information. The development in fiber optics continues to enhance considerably during the last decade, providing more and more benefits to their users.

It does not take a specialist scientist to know just how the process works. An optical fiber can be used to transmit a pulse of light in one spot to another. An electromagnetic carrier wave will be modulated in order to use the light to transfer the data. A transmitter is thus required to create the signal before is distributed across the said cable. It is important to observe that such networks also counteract any distortions to the signal, which would result in interference. When the signal is received at the other end, it’s converted into an electric signal.

Is transmission of data an issue for you together with your old networking technology? Your company should then consider installing a fiber optic network! Light is passed in the form of light pulses with an optical glass fiber. This beats the traditional way of transmitting information with the help of copper wires, because this approach to using optical fiber is quicker and is therefore a more sensible choice.

All this adds to the price of optical fiber being relatively high. Fiber optic networks are mainly suited in situations where information is transmitted to longer distances. Including several telephone companies too. These fiber optic networks can carry higher levels of data in a nutshell distances too.

The rapid growth and development of the internet in recent years has taken about the requirement for new methods to transfer information. Naturally, the faster this process is performed, the better for everyone. However, the amount of virtual traffic making the rounds the world has also been steadily increasing, so these kinds of networks have become indispensable in transferring data wisely.

Telephone companies have played the most significant part within the increasing reliance on fiber optics. Actually, numerous telecommunication companies realised the future is determined by such cables and optical solutions rather than the old copper wires of that time. The possibility of monopolizing the market drove these companies to take a position a lot in fiber optics.

Not only the larger companies use fiber optics but also the smaller business firms and personnel. Instead of using wireless networks this fiber optic technology can be easily be implemented in the home based computer networks too. These optical fibers are generally made from plastic. Anybody who wants a faster connection may use Ethernet technology at home or in the working environment Due to the low power LED bulbs been used, the constant maintenance cost of fiber optic networks are comparatively low.

In the educational sphere, fiber optic networks are also an instantaneous success. One must understand that nowadays education has become increasingly reliant on technology, so computers are playing a chief role in schools. Universities all around the world employ such networks to transfer educational matter between students and lecturers, in addition to between the students themselves.

There isn’t any doubt that these kinds of networks continues to shape the long run in regards to the change in information. More and more governments, companies and educational institutions are purchasing fiber optic infrastructure as it is clear that right now there isn’t any better alternative in the field.

However, fiber optic networks haven’t been implemented up to now in lots of parts of the country. Another major factor for that less using fiber optics is the labour charges involved with installation. The glass fiber is more sensitive than copper wires, which means that more care needs to be taken in installing and maintaining a fiber optic network. For this reason you will find several layers since the glass fiber in fiber optics.

About the author:

Fiberstore is experienced on fiber optic network products. Learn a little more about Cisco SFP and wire stripper on www.FiberStore.com.

What is Reconfigurable Optical Add-Drop Multiplexer

In the fiber optic network which uses wavelength division multiplexing (WDM), reconfigurable optical add-drop multiplexer (ROADM) is used to remotely add, block, pass or redirect modulated light emissions-infrared and visible-within a range of wavelengths.

With ROADM devices, signal switching doesn’t need optical-to-electric and electric-to-optical conversions. Instead, outgoing light beams can be generated, incoming beams could be terminated or beams could be passed through the device unmodified. This is achieved through wavelength-selective switch (WSS) components within the device.

A ROADM allows remote configuration and reconfiguration of emissions; bandwidth could be assigned when needed and without interrupting concurrent traffic, and power balancing is automatic. Most ROADM devices use technologies according to first-generation, wavelength blocking (WB) or second generation, planar light-wave circuit (PLC) technology. Whenever a wavelength change is required inside a specific channel, these technologies filter light emissions, extract data and impress data onto another emission. This method is more streamlined using PLC technology.

The different switching technologies in ROADM devices include microelectronic mirrors, live view screen, thermo-optic and beam-steering switches in planar waveguide circuits, and tunable optical filters.

ROADM devices were initially used in long-haul DWDM equipment. By 2005, metropolitan networks began using ROADMs in reaction to increased interest in Ethernet, as well as high-speed data, audio and video services. Within the ensuing years, ROADM devices have brought bandwidth flexibility and operational efficiency to networks. ROADM-based networks are enabling an automated optical layer with dynamic multipoint connectivity, independent wavelength add-drop, remote bandwidth allocation that has been enhanced power management capabilities.

Combined with the benefits of ROADM comes the inevitable need for fiber optic testing that safeguards function and helps to make sure performance. Here are common testing-related challenges to consider in ROADM-based networks.

1. Increases both in insertion loss per node and insertion loss per channel

2. The need to measure optical loss per channel for multiple ROADM configurations

3. The necessity to measure optical signal-to-noise ratios utilizing a precise and repeatable method

4. The impact of possible bandwidth thinning, other changes to bandwidth, and dispersion, that is of particular concern in multiple cascaded devices and 40 Gbit/s systems

5. Compliance using the optical transport network (OTN) standard-ITU-T G.709 standard

Unlike the optical add-drop multiplexer, Capabilities of ROADM test equipment should encompass optical spectrum analysis (OSA), and OTN performance qualifiers for newly commissioned links, along with the transport layer and all ROADM-supported interfaces. Major manufacturers of OSA and related electronic test equipment include, FiberStore, Anritsu, Digital Lightwave, Exfo and JDSU Test.

Source: http://www.fiberstore.com/

Higher Data Throughput From Multimode Fiber Patch Cables

Information available at our fingertips in form of digital data today has swelled up to levels which had never been before. At the same time, real time communication has exponentially increased to extremely high levels. A whole class of applications have emerged that demand for transmission of high-speed data.

Necessity may be the mother of invention – optical fiber networks have been invented and deployed to solve the problem of high volume data exchange. And multimode fiber patch cables have grown to be the very first choice one of the different connectors of the wired carriers with endpoint devices.

What are the speed-hungry and volume-hungry data centric applications that have created this entire demand? Some examples of those applications are the Internet, the local area multi-computer networks, the phone networks and the ATM networks. There are many more applications with intense hunger for fast communication resources. For those practical purposes, these communication channels need a high-speed network that can carry enormous volumes of data with minimal attenuation and extreme accuracy. The modern fiber optic cable technology provides exactly this sort of communication.

The multimode patch cables are used to connect this data transmitted over the network towards the devices that they target to cater. These patches may also be used to connect the two loose ends of two fiber optic cables. The patch cables have to be multimode when the requirement is to support multimode optical fibers.

What is a multimode cable poor fiber optics? A multimode is one in which multiple packets of data can be simultaneously carried across the wire. The result is that the network can carry numerous data packets at a instant of time. The multimode mainline network cables are usually short long since the target with these cables is to support high speed and high power multiuser systems in a localized sense. The patches are compatible with the network cables to enable the machine remain aligned with the network objectives. Consequently the multimode patches support multiple user applications transferring data simultaneously, as well as retain the qualities of standard single mode patches like the high network speed, low network hindrances and occasional external interferences.

It’s also interesting to note that the end point devices these patch cables connect can be heterogeneous in nature. The aperture the end point device requires and types of applications supported may be diverse. There exist several different kinds of multimode fiber patch cables you can use based upon the requirements. And depending upon the exact reason why you have to install the patch on your fiber optic network, you shall need to select your patch and go ahead with the required installation.

Source: http://www.fiberstore.com/

Several Variable Optical Attenuator Introduction

Variable optical attenuator (VOA) has a wide range of applications in optical communication, and its main function is to reduce or control the optical signal.
The basic characteristics of fiber optic network should be Variable, especially with the application of DWDM transmission systems and EDFA in optical communication, it must be carried out in a plurality of optical signal on the transmission channel gain flattening or equalization, channel power in the optical receiver. The side to be dynamic saturation control, optical networks also need to control for other signals, making the VOA become indispensable key components. In addition, VOA also can be combined with other optical communication components and this pushed itself to the characteristics of the high-level module.
In recent years, there appeared many technologies on manufacture of variable optical attenuator, including mechanical VOA, magneto-optical VOA, LCD VOA, MEMS VOA, thermo-optic VOA and acousto-optic VOA.
Mechanical VOA
The principle is to use a stepper motor drag neutral gradient filter, its output optical power at a predetermined attenuation rule change when the different positions of the light beam passes through the filter, so as to achieve the purpose of adjusting the amount of attenuation. There is also a mechanical polarized optical attenuator. Its basic principle is that the light beam emitted from the ingress port reflected by the reflection sheet to the port, the the reflector coupling efficiency between the two ports by the inclination angle of the reflection sheet to the control, enabling adjustment of the light attenuation. The inclination of the reflection sheet from a variety of different mechanisms to control. Mechanical type optical attenuator is more traditional solutions, so far, the VOA application in the system most used mechanical method to achieve attenuation. The type of optical attenuator with mature technology, optical properties, low insertion loss, polarization dependent loss, without temperature control, etc.; disadvantage is that the larger, more complex structure components, the response rate is not high, it is difficult to automate the production is not conducive to integration.
Magneto-optical VOA
Magneto-optical VOA is the use of some of the substances in the magnetic field is shown by the changes in optical properties, such as magnetic rotation effect (Faraday effect) can also be achieved attenuation of the light energy, so as to achieve the purpose of adjusting the optical signal. The magneto-optical effect of the material and in combination with other techniques, you can create a high performance, small size, high response and the structure is relatively simple optical attenuator. This is LLL device using discrete technology to produce the optical attenuator to be a further development of the field.
LCD VOA
Utilizing a liquid crystal refractive index anisotropy in the liquid crystal VOA shows birefringence. When an external electric field is applied, the orientation of the liquid crystal molecules are rearranged, will result in the change in its transmission characteristics. The type of attenuation can be achieved by light intensity change of the type of voltage control is applied to the two electrodes in the liquid crystal. The liquid crystal optical attenuator VOA can achieve the miniaturization and high response. But at the same time the liquid crystal material into a larger loss, the production process is relatively more complex, in particular, is influenced by environmental factors, its advantage is a low cost, there are commercial batch.
MEMS VOA
MEMS is the technology of the new applications in this area, After several years of development, the MEMS chip production process has become more mature, a strong impetus to the application of the MEMS optical attenuator. Optical network applications, MEMS technology-based products also have the obvious advantage on price and performance. MEMS VOA has been very mature, and mass production and large-scale application. Because of yield problems, in terms of price also facing challenges In addition, micro-electro-mechanical components, reliability is sometimes less than ideal. The early MEMS VOA using laser welding, into a larger device, and the production efficiency is low, and high assembly costs. Currently, the market also introduced a MEMS VOA plastic technology, a good solution to this problem.
Thermo-optic VOA
Thermo-optic VOA mainly using some of the material changes in the optical properties of temperature field characteristics, such as temperature changes caused by the thermo-optical refractive index change. According to the structure of the different, can be divided into two categories, leak-and open-light type VOA. Thermo-optic VOA due to heating, cooling device is relatively complex, a function of the mathematical relationship between the temperature field photoconductive medium refractive index is complex and difficult to accurately quantify and control, especially the longer response time hindered its application in modern optical communication .
Acousto-optic VOA
The basic principle is to use the cyclical strain, resulting in a periodic variation of the refractive index, equal to create a phase grating for the acousto-optical crystal in the generated under the action of ultrasonic waves, and so can be modulated using the raster beam. Some companies have already claimed to have developed the acousto-optical crystal variable attenuator (called the AVOA). It is understood that the acquisition of the acousto-optic crystal material is no problem, but at this stage of the total cost is high, about 4-5.
Conclusion:
Variable optical attenuator is one of important optical devices in the optical communication system. Over the years, it has been stuck at a mechanical level. Because its size is not conducive to integration, it is generally only suitable for single-channel attenuation. With the development of DWDM system, as well as market the flexibility to upgrade reconfigurable optical add-drop multiplexer (ROADM) potentially huge demand, there need more channels and small size variable optical attenuator array, in particular the integrated VOA product. Traditional mechanical methods can not solve these problems. With the development of fiber optic network, VOAs development trends are: low cost, highly integrated, fast response time as well as integration of hybrid with other optical communication devices.
Source: http://www.fiberstore.com/

Optical WDM in Fiber Optic Network

Optical WDM networks are networks that deploy optical wdm fiber links where each fiber link carries multiple wavelength channels.
An exciting Optical Network (AON) is definitely an optical wdm network which supplies end-to-end optical paths by using all optical nodes that allow optical signal in which to stay optical domain without conversion to electrical signal. AONs are often optical circuit-switched networks where circuits are switched by intermediate nodes in the granularity of the wavelength channel. Hence a circuit-switched AON can also be called a wavelength routing network where optical circuits are equal to wavelength channels.
A wavelength routing network includes optical cross-connect (OXC) and optical add-drop multiplexer (OADM) interconnected by WDM fibers. Transmission of information over this optical network is performed using optical circuit-switching connections, referred to as lightpaths. An OXC is definitely an N * N optical switch with N input fibers and N output fibers with every fiber carries wavelengths. The OXC can optically switch all the incoming wavelengths of its input fibers to the outgoing wavelengths of its output fibers. An OADM can terminate the signals on a quantity of wavelengths and inserts new signals in to these wavelengths. The rest of the wavelengths pass through the OADM transparently.
For a user to deliver data to some destination user, a circuit-switching connection is made by using a wavelength on each hop along the connection path. This unidirectional optical path is known as lightpath and also the node in between each hop is either an OXC or an OADM. These units are utilized within the 100G DWDM networks. A separate lightpath has to be established using different fibers to setup transmission within the opposite direction. To fulfill the wavelength continuity constraint, the same wavelength can be used on every hop along the lightpath. If a lightpath is blocked since the required wavelength is unavailable, a converter in an OXC can transform the optical signal transmitted in one wavelength to another wavelength.
Because the bandwidth of a wavelength is usually much larger than that requires by a single client, traffic glooming is used to allow the bandwidth of the lightpath to be shared by many people clients. The bandwidth of the lightpath is split into subrate units; clients can request one or more subrate units to carry traffic streams at lower rates. For instance, information is transmitted over an optical network using SONET (Synchronous Optical Network) framing with a transmission rate of OC-48 (2.488 Gbps). A lightpath is established from OXC1 to OXC3 through OXC2 using wavelength w, the subrate unit available on this lightpath is OC-3 (155 Mbps). A user on OXC1 can request any integer number of OC-3 subrate units up to a total of 16 to transmit data to another user on OXC3. A network operator can use traffic-groomed lightpaths to provide subrate transport services to the users with the addition of an online network towards the fiber optic network.
Information on a lightpath is typically transmitted using SONET framing. In the future, the data transmitted over optical network uses the brand new ITU-T G.709 standard, referred to as digital wrapper. In ITU-T, an optical network is referred to as the optical transport network (OTN). Listed here are some of the options that come with G.709 standard: 1) The conventional permits transmission of various kinds of traffic: IP packets and gigabit Ethernet frames using Generic Framing Procedure (GFP), ATM cells and SONET/SDH synchronous data. 2) It supports three bit rate granularities: 2.488 Gbps, 9.95 Gbps and 39.81 Gbps. 3) It offers capabilities to monitor an association on an end-to-end basis over several carriers, in addition to over a single carrier. 4) G.709 uses Forward Error Correction (FEC) to detect and correct bit errors brought on by physical impairments in the transmission links.
Lightpath may either be static or dynamic. Static lightpaths are in place using network management procedures and may remain up for a long time. Virtual Private Networks (VPN) could be set up using static lightpaths. Dynamic lightpaths are established instantly using signaling protocols, such as GMPLS (Generalized Multi-Protocol Label Switching) and UNI (User Network Interface) proposed by OIF (Optical Internetworking Forum). GMPLS is definitely an extension of MPLS and is built to apply MPLS label switching techniques to Time Division Multiplexing (TDM) networks and wavelength routing networks, in addition to packet switching networks. The OIF UNI specifies signaling procedures for clients to automatically create, delete and query an association over wavelength routing network. The UNI signaling is implemented by extending the label distribution protocols, LDP and RSVP-TE.