The Application of Optical Passive Components in WDM System

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.


Warm Tips:  TX – Transmitter                    RX – Receiver

                     WL – Wavelength Locker       MOD – Modem

                      FM –  Filtration Module       OXC – Optical Cross Connect

                      OADM – Optical Add Drop Multiplexer

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.

Fiberstore’s several important fiber optic product categories

Sometimes you know, whenever inside a fiber optic network system, the requirement occurs to lessen or even stability the ability from the gentle sent in one gadget to a different gadget. Nicely, the fiber optic attenuator can be used in such instances. They could manage the actual result from the fiber gentle energy degree. fiber optic attenuator are utilized with regard to decreasing the ability from the gentle within the fiber optic system.

fiber optic attenuator

The fiber Optic Attenuator can be used slow up the energy inside a optical signal. Obtainable in 1310nm in order to 1550nm. The actual optical attenuator is really a man in order to woman settings as well as connectorized having a FC, SC/APC, ST, PC, LC, UPC, MU, FC/APC, SC, LC/APC, set worth connect kind fiber optic attenuators, inline fiber optic attenuators, adjustable fiber optic attenuators. Typical attenuation ideals tend to be 5dB, 10dB, 15dB as well as 20 dB however all of us share just about all dimensions through 1dB in order to 25db.

Attenuation is actually losing optical energy because gentle moves lower the fiber. It’s calculated within sound levels (db/km). On the arranged range, the fiber having a reduce attenuation enables much more capacity to achieve it’s recipient than the usual fiber along with greater attenuation. Nicely, there’s a brand new item, Fiberstore give a moderate with regard to modifying the actual transmission. The look is actually perfect for set up in to OEM gear. In-line attenuators tend to be avaiable along with attenuation ideals which range from 1-20 dB and may end up being ended along with any kind of solitary setting connection or even remaining unterminated with regard to splicing.

Fiberstore provide 2 kinds of  fiber optic attenuators, set fiber attenuators make reference to the actual attenuator that may slow up the energy associated with fiber gentle in a set worth reduction, for instance, 5dB. Whilst flexible fiber optic attenuator make reference to the actual attenuator that may produce the flexible Reduction towards the fiber optic hyperlink. All of us provide fiber attenuator sequence consist of: SC,FC,LC,ST,MU,SC / APC,FC/ APC, solitary setting fiber optic attenuator as well as multimode fiber optic attenuator obtainable. The fiber optic attenuators tend to be produced based on worldwide regular and therefore are suitable for the actual fiber optic items now available within the worldwide marketplace. fiber optic attenuators could be made to make use of along with types of fiber optic fittings. the actual attenuators could be woman in order to woman which is sometimes called bulkhead fiber optic attenuator or even man in order to woman that is also known as the connect fiber optic attenuator. An additional kind inline fiber optic attenuator was created along with a bit of fiber optic cable television from any kind of duration as well as fittings tend to be set up since the clients ask for.

A good optical splitter is really a unaggressive gadget which divides the actual optical energy transported with a solitary enter fiber in to 2 result materials. The actual enter optical energy is usually divided equally between your 2 materials. This kind of optical splitter is actually a Y-coupler. Nevertheless, a good optical splitter might deliver the actual optical energy transported through enter energy within an unequal method. A good optical splitter might divided the majority of the energy in the enter fiber in order to among the result materials. Just a tiny bit of the ability is actually combined to the supplementary result fiber. This kind of optical splitter is actually a T-coupler, or even a good optical faucet. Fiberstore’s optical splitter is actually broadly recognized as well as utilized in unaggressive optical systems, specifically for situations in which the divided settings is actually scaled-down (1×2, 1×4, 1×8, 1×16, 1×32 fiber splitter and so on.)

Fiberstore system press converters. Utilized like a ethernet in order to fiber converter. The actual press converters may change indicators amongst Ethernet, Quick Ethernet, Gigabit Ethernet, T1/E1, DS3, ATM, Sixth is v. thirty-five, and so on. Fiberstore systems may be the recognized professional within the press converters region; their own changeover systems press converters consider probably the most component on the planet marketplace with this area.

media converter

Fiberstore’s ethernet media converter is utilized within Cisco Techniques, IBM, Nortel, Ms as well as ADC. By utilizing the press converters, these types of globe top businesses reduce their own wiring price. Depending on Changeover Stage Program benefits, customers might conserve the price whilst don’t break down the actual system overall performance. Fiberstore try to work along with user’s been around system gear without having impacting it’s look as well as entire overall performance. Fiberstore press converters tend to be becoming a lot more utilized all over the world. The top quality as well as dependable fiber optic press converters can be found in many types. If you don’t Begin to see the kind you are searching for, after that simply deliver Fiberstore a fast e-mail as well as we’ll have the ability to possibly find the precise kind you’ll need or even we’ll produce this.

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MEMS Based Variable Optical Attenuators

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.