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Trends In Fiber Optic Communication Industry

Trends In Fiber Optic Communication Industry

Fiber optic communication industry has been enjoying amazing growth for nearly 20 years, which is driven by both technology advance and market demand. There are some obvious trends inside the growth and development of new technology and market. All-Optical Network and Multi-Terabit Networks could possibly be the first two.

All-Optical Network
All-optical network has become a top topic in fiber optic communication niche for over a decade. Its ultimate goal would be to process all signals in the optical domain with no conversion and controlling to electrical domain in any way.

However, most signal routing, processing and switching occur in the electrical domain up to now. Optical signals must be converted to electrical signal first, and then the electrical signals are processed, routed and switched to their final destination. Following your processing, routing and switching, the electrical signals will be converted to optical signals which can be then transmitted over long distances. This technique is called the O-E-O process.

But this O-E-O process severely limits the rate with the network. Why? Since optical signals can process data faster then today’s electronics. The O-E-O process is a bottleneck preventing us from achieving even higher data rates. This bottleneck results in a tremendous interest in all-optical networks where no electronics are required for signal processing, routing and switching.

The advantage of all-optical network is that since all signal processing, routing and switching occurs in optical domain, there is no need to switch the electronics when data rates increase. For instance, current fiber optic transmitters and receivers are equipped for just one single data rate, thus, they ought to be replaced if the data rate increases. But this won’t be necessary in a all-optical network.

Admittedly, all-optical network involves be trend of fiber optic communication. However, many obstacles still lie in our approach to make all-optical network a real possibility. Some functions for example reading headers about the optical signals, switching the optical signal on the fly in line with the header content and real-time wavelength switching are just a few of the serious challenges that should be solved before we are able to have a true all-optical network.

Multi-Terabit Networks
DWDM opens the door to multi-terabit transmission. The interest in developing multi-terabit networks is driven through the increasing accessibility to more bandwidth in fiber optic networks.


One terabit network was achieved by using 10Gb/s data rate combined with 100 DWDM channels, while four terabit network may be accomplished by combing 40Gb/s data rate with 100 DWDM channels too. Researchers move their target to even higher bandwidth with 100Gb/s systems. This kind of speed is extremely expensive for make and may just be justified on long-haul systems. However with the price reduction on fiber optic components, devices and systems, more bandwidth is not definately not us.

There are a few other major trends in the fiber optic communication industry too. The most important ones include expansion into mass markets (FTTx), miniaturization, new technology development, cost reductions and even more.

About the author:
Morph Sun is a fiber optic network expert in FiberStore(FS). FS is a best fiber optic products supplier who can offer most FTTx solutions including CWDM/DWDM modules, transceivers, fiber optic cables, patch cables and so on. For more information such as fiber cable price, figure 8 fiber optic cable and plastic optical fiber, please visit our website.

What does an Optical Attenuator do

What does an Optical Attenuator do

An optical attenuator is a device commonly used to lower the amount of power of an optical signal in a fiber optic communication system. In fiber optics, attenuation can also be called transmission loss. It’s the reduction in light signal intensity with regards to the distance traveled by the signal inside a transmission medium. Attenuation is an important element to limit the transmission of the digital signal driving considerable distances. Optical attenuator reduces this optical signal because it travels along a totally unoccupied space or perhaps an optical fiber.

Optical fiber attenuators may employ several principles when utilized in fiber optic communications. One common principle may be the gap loss principle. Attenuators by using this principle are responsive to the modal distribution ahead of the attenuator. Thus, they should be utilized at or close to the transmitting end. Otherwise, the attenuators could establish less loss than intended. This problem is avoided by attenuators which use absorptive or reflective principles.

You will find three basic types of optical attenuator: the fixed attenuator, step-wise attenuator and the continuously variable attenuator. Fixed attenuators reduce light signals by a specific amount of negligible or no reflection. Because signal reflection isn’t an issue, fixed attenuators are known for more accurate data transmission. Principal components associated with fixed attenuators include the flatness over a specified frequency, range, voltage standing wave ratio (VSWR), the quantity of attenuation, average and peak power-handling capability, performance over a specific temperature, size and height. Fixed attenuators are also often accustomed to enhance interstage matching in an electronic circuit. Thornton’s fixed attenuators can be found from 5 dB to 25 dB. Mini-Circuits’ fixed attenuators are packaged in rugged plug-in and connector models. They are available in both 50- and 76-ohm models which range from 1to 40 dB spanning DC to 1500 MHz.

In variable optical attenuators (VOA), resistors are replaced with solid state devices like the metal semiconductor field effect transistor (MESFETs) and PIN diodes. VOA attenuates light signal or beam inside a guarded manner. Thus producing an output optical beam with various attenuated intensity. The attenuator adjusts the ability ratio between your bright beam from the tool and the light beam entering the device over a changeable rate. VOA is usually used in fiber optic communication systems to manage optical power levels in order to prevent damages in optical receivers which may be due to irregular or fluctuating power levels. Price of commercial VOA varies depending on the manufacturing technology used.

Fiberstore claims that it is optical attenuator units produce precision amounts of attenuation, utilizing the added flexibility of adjustment. Fiberstore’s variable attenuators can be found in single mode and multi-mode versions. They have low insertion loss and back reflection. The attenuators will also be compact in dimensions and obtainable in multiple packaging options. These attenuators could be adjusted in milliseconds with a simple square wave bias between 0 and 10 volts.

Brief Introduction to Optical Switch

Brief Introduction to Optical Switch

The advent and development of fiber optic communication technology has brought a revolutionary change to the communications industry. Nowadays in the world, about 85% of communication services via optical fiber transmission, long haul network and local relay network has been widely using fiber optics.

Dense Wavelength Division Multiplexing (DWDM) technology development and maturation has opened up a vast space for the full application of the bandwidth and capacity of optical fiber transmission. With a high rate, large bandwidth obvious advantage, DWDM optical communication network has become the development of communication network trend. Especially in recent years, an IP-based Internet business explosive growth, this growth trend has not only changed the relationship between the IP network layer and the underlying transport network, and the networking of the entire network, the node design, management and control new requirements.

An intelligent network architecture – Automatic Switched Optical Network (ASON) has become a research hotspot of today’s systems. Its core node optical cross-connect (OXC). Constitute dynamic wavelength routing and optical network flexible and effective management can be realized by the OXC equipment. OXC technology is one of the key technologies increasingly complex DWDM network, optical switch for switching the optical path of functional devices, is a key part of the OXC. Optical switch matrix is ​​the core part of the OXC, it can achieve dynamic optical path management, optical network fault protection, wavelength dynamic allocation function, the solution to the current complex network of wavelength contention and improve the wavelength reuse, flexible configuration of the network are There is of great significance.

Optical switch is not only the core device in OXC, but also widely used in the following areas.

(1) Optical network protection switching system, the actual optical transmission system have left spare fibers when working channel transmission interruption or performance degradation to a certain extent, the main signal light switch automatically go to standby fiber system transmission, so that the receiving end received normal signal and feeling less than the network has a fault, the network nodes connected in a ring to further improve the survivability of the network.

(2) Real-time network performance monitoring system, remote fiber test points, 1 × N multi-channel optical switch, a plurality of optical fibers connected to the Optical Time Domain Reflectometer, real-time network monitoring, computer-controlled optical switch switching sequence and time to achieve the detection of all fiber, and test results are returned to the network control center, once found a road problems, can be processed directly in the network management center.

(3) The light switch is also used in optical fiber communication device testing system and metropolitan area networks, the poor access network/multiplexing and switching equipment. The introduction of the light switch in the future all-optical networks more flexible, intelligent, survivability. Optical switching technology has become the key to future optical networking, optical switching technology plays an increasingly important role in the field of communication, automatic control.

In many types of optical switches, MEMS optical switch is considered most likely to become the mainstream of the optical switch device. In this paper, an overview of the basis of the principle characteristics of a variety of optical switch on, the focus of several major MEMS optical switch, and outlined their structure and performance characteristics.

What is Wavelength Division Multiplexing Technology?

What is Wavelength Division Multiplexing Technology?

Wavelength division multiplexing (WDM) technology is an optical communication technology using frequency division multiplexing of optical domain to achieve simultaneous transmission on a single fiber channel optical signal. Wave-division multiplexing standard has large system capacity, high utilization of fiber optic long distance transmission line transmission equipment, capacity expansion and upgrade convenient, and is the best solution to provide ultra-high-speed, high-capacity optical fiber communication.

Dr. Gao Kun, the 1966 British Chinese dielectric waveguide theory first proposed optical fiber can be used for optical communication of scientific proof. 1970 Corning Glass Company first manufacturing an optical fiber in the world’s first, was the loss of 20 dB per kilometer, improved soon reduced to 4dB. In 1976 the world’s first test line in the optical fiber communication systems in Atlanta, United States of Bell Labs underground pipes come out the following year in Chicago, the commercial trials of fiber-optic communication systems. 80’s optical fiber communication in the world boomed. The 80’s world widely used on the digital transmission system prevail synchronization (Plesiochronous) system, but these quasi-synchronous system the existence of system standards are not unified, equipment Picture clutter, not suitable for the development of optical communications. To this end, the United States proposed a fiber-based, synchronous communication network (SONET), as the foundation of modern communication platform. 1988 CCITT based on the concept of SONET modify and develop synchronous communication system (SDH) standards. Multiplexing SDH system with a unified standard interface, synchronization, automatic cross-connect directly to the upper and lower support grid signal, and has been the widespread use of the world’s powerful network management capabilities. Currently used in fiber optic network systems in the world, basically SDH systems. With the advent of the information age, the rapid increase of the amount of information transmission, fiber-optic communications increasingly to the development of large capacity, ultra high-speed WDM systems.

WDM technology is the first to use the birthplace of the optical fiber in the United States. Construction company by AT & T in the 1980s, known as the “Northeast Corridor” Cable Link project using WDM technology. WDM technology within a wavelength window of the fiber, but also can be used in the different windows. 90’s due to the time division multiplexing (TDM) technology, the rapid development of its technology is simple, practical, predominate in the field of optical communications, WDM development is not rapidly, WDM technology until 1995 before entering the exuberant development period. Lucent has pioneered 8X2.5Gb/s system, then Ciena launched 16X2.5Gb/s system. Present in the test chamber has reached a rate of Tb/s.

Begin with a fiber optic communication multiplexing original PCM Pulse Code Modulation way coaxial cable used, the analog signal into a digital signal and then using the time division multiplexing technology to form a group to five groups. This system is what we call the PDH system. Later improvements SDH Series: STM-1 (155Mbit/s), STM-4 (622Mbit/s) and STM-16 (2.5 Gbit/s), such as the use of multiplexing is still TDM technology. Since electricity TDM mostly use 2.5Gbit/s, and when transmission over 10Gbit/s, will encounter some difficulties. WDM technology using a plurality of wavelengths on a fiber for transmitting the optical signal has been recognized by the industry, the well is considered to be the main development of the optical fiber communication technology, the use of WDM techniques can be transmitted on each fiber at the same time the n-way optical carrier, thus its capacity to rapidly expand n times. Of 2.5Gbit/s rate has reached in SDH systems, the transmission rate is no longer the performance bottleneck of modern communication, people’s pursuit of large capacity and broadband is the fiber-optic system.

WDM technology refers in fiber low loss and dispersion coefficient a small 1550nm window, using a demultiplexer Hop liquid, using a frequency division multiplexing in the optical domain using FDM technology, each wavelength path to achieve multi-channel frequency domain segmentation The simultaneous transmission of a light signal in an optical fiber technology. Each transmission wavelength of the signal is independent of each other, each wavelength channel can transmit SDH 2.5Gbit/s digital signal or a higher rate of the digital system. Requires the use of wavelength division multiplexer (combiner) optical carrier signals of different wavelengths are combined fed the same fiber; again at the receiving end a wavelength division multiplexer (demultiplexer) of these different wavelengths at the transmitting end bearing optical carrier of different signals to be separated. Depending on the wavelength division multiplexer, the number of wavelengths can be multiplexed are not the same, ranging from a few to dozens. General commercialization for the of 8 wavelength system and the 16-wavelength system.

The one hand, the development of the WDM technology, thanks to the transmission lasers and the reception filter technology improved, so that the wavelength of the optical carrier can be a gap in the case of no road occasion crosstalk caused reduced, thereby improving the transmission capacity of optical fiber systems. The other hand, thanks to the success of the EDFA technology, so that the multiplexed optical signal can be obtained from the same the EDFA gain, and can within the greater the width of the pulse width to provide a flat gain, so that a small gap multiplexed optical carrier may be used in combination same EDFA. WDM supporting technology: light source technology, optical fiber technology. Optical to receive filtering technique, partial wave combiner technology, optical amplification technology and monitoring technology.