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Have a Special Look at Fiber Optic Amplifier

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An optical amplifier is a device that amplifies an optical signal directly, without the need to first convert it to an electrical signal. An optical amplifier may be thought of as a laser without an optical cavity, or one in which feedback from the cavity is suppressed. Optical amplifiers are important in optical communication and laser physics.
Standard of Fiber Optic Amplifier
We know Fiber Optical Amplifiers that design from simple single stage to more complex multistage amplifiers with variable gain evolved as a different viator for system performance by equipment manufacturers and were initially made in house. More recently, the equipment vendors outsourced the design and manufacturing of amplifiers to the component vendors while requiring more than one source in order to control cost and delivery risk. This led to a pseudo-standardization of optical amplifiers with three or four vendors making amplifiers with compatible optical, mechanical,electrical hardware, and software specification.
Optical amplifier is dominated by erbium-doped fiber amplifiers and the leading suppliers have been shipping amplifiers for 10 years or longer. These companies include Oclaro, JDS Uniphase, and Furukawa. Ovum estimates these companies enjoy more than 60% market share of the nearly 200 dollars merchant erbium-doped fiber amplifier market in 2008. Well fiber-mart’s In-line Amplifier is on hot sale.
There are another 25 companies fighting for the remaining revenues. Twenty-one of the remaining optical amplifier companies that still exist today started between 1997 and 2003. All the amplifier suppliers in low cost regions started between 1998 and 2003. And only two new amplifier suppliers have entered the market since 2003, Manlight and Titan Photonics. The Figure showed the optical amplifier for next WDM networks
optical amplifier
After nearly five years of focus on cost reduction and reduces progress in innovation. New direction in optical amplifier technology are becoming visible. These are in response to the major trends for the amplified optical networks of higher degree of connectivity and introduction of channels at higher data rates. Agility in amplifiers will be key to the successful deployment of ROADM networks requiring seamless provisioning and recovery in the event of failures. Features such as fast gain control at sub millisecond timescale and rapid spectral adjustments to counter the impairments due to higher order effects (spectral hole during[SHB], Raman spectral tilt in fiber, and polarization dependent loss [PDL]) of components) will be needed on an integrated basis across the whole system. Likewise, continuous demand to increase the OSNR of the signals to support ever increasing channel rates to 100 Gb/s and beyond over ultra-long-haul distances will require every dB to be made available, for example by deployment of hybrid Raman/EDFAs at every repeater site in the network. Another trend is the deployment of high-power cladding pumped amplifiers with watts of output power in the access network for distribution of video and other content. From the commercial standpoint, however, since the industry has become addicted to 15% to 20% price reduction year to year, these new features will have to be delivered at negligible incremental cost.
Warm tips: fiber-mart is a professional fiber optics products supplier, includes different fiber optical amplifier, such as Booster Amplifier, CATV fiber amplifier, DWDM amplifier and EDFA amplifier, even Fibre Splitter, if there you need, welcome to visit our main website: http://www.fiber-mart.com

Do you know Fiber Optical Transponders?

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As we know, transponder is important in optical fiber communications, it is the element that sends and receives the optical signal from a fiber. A transponder is typically characterized by its data and the maximum distance the signal can travel.
Functions of a Fiber Optical Transponder includes:
Electrical and optical signals conversion
Serialzation and deserialization
Control and monitoring
Applications of Fiber Optical Transponder
Multi-rate, bidirectional fiber transponders convert short-reach 10gb/s and 40 gb/s optical signals to long-reach, single-mode dense wavelength division multiplexing (DWDM) optical interfaces.
The modules can be used to enable DWDM applications such as fiber relief, wavelength services, and Metro optical DWDM access overtay on existing optical infrastructure.
Supporting dense wavelength multiplexing schemes, fiber optic transponders can expand the useable bandwidth of a single optical fiber to over 300 Gb/s.
Transponders also provide a standard line interface for multiple protocols through replaceable 10G small form-factor pluggable (XFP) client-side optics.
The data rate and typical protocols transported include synchronous optical network/synchronous digital hierarchy (SONET/SDH) (OC-192 SR1), Gigabit Ethernet (10GBaseS and 10GBaseL), 10G Fibre Channel (10 GFC) and SONET G.709 forward error correction (FEC)(10.709 Gb/s).
Fiber optic transponder modules can also support 3R operation (reshape, retime, regenerate) at supported rates.
Often, fiber optic transponders are used to for testing interoperability and compatibility. Typical tests and measurements include litter performance, receiver sensitivity as a function of bit error rate (BER), and transmission performance based on path penalty.Some fiber optic transponders are also used to perform transmitter eye measurements.
fiber-mart.com Provides Optical Transponders Solution
Let’s image that the architecture that can not support automated reconfigureability. Connectivity is provided via a manual Fibre Optic Patch Panel, a patch panel where equipment within an office is connected via fiber cables to one side (typically in the back), and where short patch cables are used on the other side (typically in the front) to manually interconnect the equipment as desired.  There is a point that Fibre Optic Patch Panel, people usually different ports patch panel , for example, 6, 8, 12, 24 port fiber patch panel and they according to different connectors to choose different patch panel, such as LC patch panel,  LC patch panel,  MTP patch panel…
The traffic that is being added to or dropped from the optical layer at this node is termed add/drop traffic, the traffic that is transmitting the mode is called through traffic. Regardless of the traffic type, note that all of the traffic entering and exiting the node is processed by a WDM transponder. In the course of converting between a WDM-compatible optical signal and a client optical signal, the transponder processes the signal in the electrical domain. Thus, all traffic enters the node in the optical domain, is converted to the electrical domain, and is returned to the optical domain. This architecture, where all traffic undergoes optical electrical (OEO) conversion, is referred to as the OEO architecture.

MEMS Based Variable Optical Attenuators

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It is commonly known that fiber optic attenuators are used in fiber optic communications, as fiber optic tester tools to test power level margins by temporarily adding a calibrated amount of signal loss, or installed permanently to properly match transmitter and receiver levels. According to its stability, it divided into fixed fiber optic attenuators and variable optical attenuators. Variable fiber optic attenuators generally use a variable neutral density filter, with advantages of being stable, wavelength insensitive, mode insensitive, it offers a large dynamic range.
With the rapid increases in traffic on optical telecommunications systems, there is an active program for developing transmission devices for use in wavelength division multiplexing (WDM), which is becoming mainstream technology for providing higher transmission speeds and a larger number of signal channels. It has been suggested that in the WDM systems of the future, variation in power due to the wavelength could be reduced a the quality of transmission improved by adjusting the power after demultiplexing into individual signals wavelengths. It is envisaged that the current method, in which the power of all the multiplexed optical signals is adjusted by a single variable optical attenuators (VOA) would give way to a method in which one VOA is used for each wavelength. Given the number of multiplexed wavelengths, this change will require VOAs that are considerably more compact. Against this background, There have developed a VOA using micro-electromechanical system (MEMS) technology with loss characteristics that have low wavelength dependence.
Single-mode fiber was used as the input and output of the VOA developed here, with a graded index fiber having the same diameter, 125um, as the SMF fusion spliced for a specified length, to form an optical coupling with a lens function. An anti-reflection coating is applied to the tip of the GIF (graded index fiber). GIF tip is polished at an angle so that the light beam emitted from the end of the GIF is not aligned with the optical axis of the fiber, but is at an angle to it. This angled optical beam is interrupted by means of a shutter that has been formed by inductively-coupled plasma deep reactive ion etching. The MEMS chip uses a silicon-on-insulator wafer, with the shutter, actuator and fiber grooves formed simultaneously on the chip by ICP-DRIE, followed by metal vapor deposition over the whole chip.
The actuator of the MEMS chip is of the comb type, and the GIF is held in the fiber grooves by means of adhesive. The MEMS chip with this GIF optical coupling system is fixed by adhesive within a casing, which is hermetically sealed.
MEMS variable optical attenuators are variable in three different configurations. The VA series works in transmission, whereas the VP series uses reflection to modulate the attenuation. The VX series is the VP or the VA series in mint plastic packing. In terms of performance, the VP series achieves lower insertion loss and better Polarization dependent loss characteristics. Whereas the VA series allows for an easier array integration and is the lower cost.
FiberStore offers a full line of optical attenuator variable testers, they are often combined with an active system component to maintain optical power on a network even if the power changes in the input signals. Our automatical variable optical attenuators are specifically designed for use in DWDM networks with individual channel source elements such as add/drop transmitters. The cost and performance characteristics of our automatically variable optical attenuators are specifically targeted to allow for the use of these devices in volume as principal DWDM channel stabilization components.

The Application of Optical Passive Components in WDM System

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Based on the DWDM technology, the all-optical network make full use of fiber optic cables which have huge transmission capacity, it must be the next-generation high reliability, fast speed information network technology. Fiber optic attenuators are widely and important optical passive components, especially in the all-optical network.
Optical attenuator is applied into WDM system upstream and downstream node channel, power balance, EDFA gain flatness, optical communication lines, system evaluation, research and adjustments, correction and so on. It is in accordance with customers’ requirements by absorbing or reflecting off part of the optical power and then reduce the signal power as expectation. It’s position in the optical fiber network just shown in the figure.
In the WDM system, EDFA is a necessary component, it is quite important for achieving all-optical network communication. However, because of the limitation of gaining window ports for EDFA, it makes different wavelengths have different gain multiplier, it leaded to energy imbalance between the channels of a WDM sytstem. Then it will result in following three problems:
Received Energy imbalance will beyond the allowed dynamic range finally.
Accumulation of SNR imbalance can cause gain of a certain wavelength of BER, it may lower than the required BER (bit error rate).
Because of the shortage of the gain, the minimum signal power of the channel may be lower than the sensitivity of the receiver.
In the DWDM optical network which has multiple contact node, such as MAN, the transmission distances and the volume of the business between the different channels are different, each channel’s transmission must be balanced, including power, BER, signal to noise ratio and so on. The application of variable fibre optic attenuator is the first solution in the system.
Moreover, optical attenuators are also important for optical telecommunication link and the test for the system. Fiber optic cable link and the system need to be examined before laying them, then it can insure some performance parameters of the system or link road, so that it is easy to do some optimization test. So we need to simulate the actual situation, mainly the proper attenuation for the signal, then we will find out the actual situation after the long distance transmission.

What Should You Know about Low-Smoke Zero Halogen Cables

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Halogen is a nonmetallic elements such as fluorine, chlorine, iodine or bromine. It is generally used as flame inhibitors in many plastics, including PVC that goes into cable insulation and electronic products. Halogens are a group of chemical elements including iodine, bromine, fluorine, astatine, and chlorine. When these elements are exposed to fire, they form hazardous gases which are harmful to harm the eyes, nose, lungs, and throat.
LSZH is a material category used to classify cable insulation. LSZH (Low Smoke Zero Halogen) cable insulation is made of materials designed to give of reduced smoke and no halogen when exposed to fire. When combined with other fire deterrents and control practices, Zero Halogen Cables can help reduce fire related casualties and property destruction. These cables will also don’t give off hazardous gas/acids or toxic smoke when exposed to fire.
LSZH cables decrease the extent of smoke produced through fire and is normally used in inadequately ventilated areas, for instance, airplane and some areas that people may be affected by smoke and toxic fumes.
Beside the halogen free features, LSZH cable also has lighter weight, this is convenient especially if the cables are run overhead in a dropped ceiling. At the same time, the impact of halogen free cables will also be lower if there is a fire because there are fewer toxic chemicals involved.
Many different Fiber Optic Cable suppliers are now making low-smoke, zero-halogen cables. And it is currently widely used in Europe and elsewhere in the world contains halogens. The European market is demanding that cables used in LANs. WANs, etc. Meet LSZH specification. The IEC 60332-1 governs the Flame Retardant Grade specifications in reference to LSZH cable.
Essentially the compound used in manufacturing cables meeting the above specifications reduces the amount of dangerous/poisonous gases in case of fire. The main difference in specifications between IEC 60332-1 versus UL 5181, UL 1666 and UL 910 is that the cable under the IEC specifications continue to burn while still emitting very low gases. UL specs demand that the flame be extinguished, but it can still be emit poisonous/dangerous gases.
Most safety advocates are calling for the used of LSZH cables, especially for the plenum space. Review your local building codes to determine if you must use LSZH cable. Non-LSZH cables will produce corrosive acids if they are exposed to water when burned; such acids may theoretically further endanger equipment.

What Types of Optical Fiber Should I Choose and How Many Fibers?

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It may be familiar for you that optical fibers are divided into two different mode which is multimode and single mode.
Single mode fiber has a core that is 8.3 microns in diameter. Single-mode fiber requires laser technology for sending and receiving data. With a laser used, light in a single mode fiber also refracts off the fiber cladding. Single-mode has the ability to carry a signal for mile, making it ideal for telephone and cable television on providers.
Multimode fiber, as the name suggests, permits the signals to travel in multiple modes, or pathways, along the insides of the glass strand or core. It is available with fiber core diameters of 62.5 and a slightly smaller 50 micron. 62.5 micron multimode is referred to as OM1. 50-micron fiber is referred to as OM2, OM3, and the recently added OM4. OM4 has greater bandwidth than OM3 and OM3 has greater bandwidth than OM2.
While single mode fiber has a core that is 8.3 microns in diameter. Single-mode fiber requires laser technology for sending and receiving data. With a laser used, light in a single-mode fiber also refracts off the fiber cladding. Single-mode has the ability to carry a signal for mile, making it ideal for telephone and cable television on providers. 50-micron OM3 fiber is designed to accommodate 10 Gigabit Ethernet up to 300 meters, and OM4 can accommodate it up to 550 meters. Therefore, OM3 and OM4 fiber are always chosen over the other glass types. In fact, nearly 80% of 50-micro fiber sold is OM3 or OM4
Except for the fiber mode, the number of fibers is necessary to know. Usually, unless you are making patch cords or hooking up a simple link with two fiber, it is highly recommended that you include a number of spare fibers. Corporate network backbones are often 48 fibers or more. Most backbone cables are hybrids – a mix of 62.5/125 multimode fiber for today’s networks and single-mode fiber for future networks. If the slowest network planned today is as gigabit speeds, it might even be better to use the new 50/125 multimode fiber optimized for the laser sources used in gigabit networks.