Category Archives: Optical Attenuators

Variable Optical Attenuator Description


High intensity, coherent light beams are used as an increasingly common means of transmitting data. Optical fibers provide higher data rates with lower cost, weight and volume per units of length than cables relying on metallic conductors.

A variety of devices are known for controlling the light beam. Once of these is the fibre attenuator.

An exemplary optical attenuator is described and shown in U.S. NO. 4,192,573 to Brown, Jr.ct al. A flat mirror reflects an input beam of light. A focusing mirror receives the beam of light reflected from the flat mirror, so that the axis of the beam of light reflected by the focusing mirror is offset from and, parallel to, the axis of the input beam of light. A pinhole assembly receives the beam of light reflected from the focusing mirror. The pinhole assembly has a pinhole positioned on the axis of the beam of light reflected by the focusing mirror. A servo-motor actuates the flat mirror and the focusing mirror, in unison, relative to the pinhole assembly in a direction parallel to the axis of the input beam of light. The parallel movement of the mirror acts to vary the proportion of the input beam of light that passes through the pinhole. The servo mechanism is bulky and requires a relatively long period of time to move the mirrors relative to the pinhole assembly.

The present invention is a variable optical attenuator (VOA) which has a semiconductor micro-electro-mechanical device for positioning a reflecting surface in any of a plurality of positions, each providing a respectively different amount of attenuation.

The variable optical attenuator includes a Icns, a first optical waveguide, and a second optical waveguide. A semiconductor micro-electro-mechanical device is positioned on a side of the lens opposite the first and second optical waveguides. The device has a reflecting surface. The reflecting surface has a normal position in which light from the first waveguide reflects off of the reflecting surface and passes through the lens into the second waveguide. The reflecting surface has a plurality of respectively different attenuation positions in which light from the first waveguide reflects off of the reflecting surface and passes through the lens, but an amount of light entering the second optical waveguide is attenuated by respectively different amounts corresponding to the respectively different positions.

According to a further aspect of the invention, a method for controlling a beam of light includes providing a lens, first and second optical waveguides, and a semiconductor micro-electro-mechanical device positioned on a side of the lens opposite the first and second optical waveguides. The devices having a reflecting surface. The reflecting surface is pivoted to a normal position in which light from the first waveguide reflects off of the reflecting surface and passes through the lens into the second waveguide. The reflecting surface is pivoted to a plurality of respectively different attenuating positions in which light from the first waveguide reflects off of the reflecting surface and passes through the lens, but an amount of light entering the second optical waveguide is attenuated by respectively different amounts corresponding to the respectively different positions.

Using Fiber Optic Attenuators to Increase Bit Error Rate

Fiber optic systems transmission ability is based on the optical power at the receiver, which is reflect as the bit error rate, BER is the inverse of signal-to-noise ratio, high BER means poor signals to noise ratio. Too much power or too litter power will cause high bit error rates.

When the power is too high as it often is in short single-mode systems with laser transmitters, you can reduce receiver power with an fibre attenuator. Attenuators can be made by introducing an end gap between two fiber, angular or lateral misalignment, poor fusion splicing, inserting a neutral density filter or even stressing the fiber. Both variable and fixed attenuators are available.

Variable attenuators are usually used for margin testing, it is used to increase loss until the system has high bit error rate. Fixed attenuators may be inserted in the system cables where distances in the fiber optic link are too short and excess power at the receiver causes transmission problems.

Generally, multimode systems do not need attenuators. Multimode source, even VCSELs, rarely have enough power output to saturate receivers. Single mode system, especially short links, often have too much power and need attenuators. For a single mode application like analog CATV systems, the return loss or reflectance is very important. Many types of attenuators suffer from high reflectance, so they can adversely affect transmitters just like highly reflective connectors.

Attenuators can be made by gap loss, or a physical separation of the ends of the fibers, including bending losses or inserting calibrated optical filters. Choose one type of attenuator with good reflectance specifications and always install the attenuator at the receiver end of the link. It is very convenient to test the receiver power before and after attenuation or while adjusting it with your fiber optic meters at the receiver, plus any reflectance will be attenuated on its path back to the source.

When testing the system power, turn on the transmitter, install the attenuator a the receiver, use a fiber optic power meter set to the system operating wavelength. Check to see whether the power is within the specified range for the receiver. For accurate measurements, the fiber attenuators connector types much match the lanch and receive cables to be tested, e.g. LC fibre optic attenuators is needed to work with the LC fiber patch cable, it work in 1250-1625nm range with optional attenuation value from 1dB to 30dB.

If the appropriate attenuators is not available, simply coil some patch cord around a pencil while measuring power with your fiber optic power meter, adding turns until the power is in the right range.

Four Types Of Common Optic Components

Optical components include lasers, splitters, multiplexers, switches, photodetectors and other receiver types,and other building blocks of fiber optic communications modules, line cards, and systems. FiberStore provide many types of optical components,such as fiber splitters,optical attenuator,fibre connector,fiber optic transceiver modules and so on. We will not regularly updated -product, tutorials, blog and other related information, sharing of information about fiber optic communication.

Common Optic Components:

The First,Fiber Splitters. The Fiber Optic Splitter, also named beam splitter, is based on a quartz substrate of integrated waveguide optical power distribution device, the same as coaxial cable transmission system, The optical network system also needs to be an optical signal coupled to the branch distribution, which requires the fiber optic splitter, Is one of the most important passive devices in the optical fiber link, is optical fiber tandem device with many input terminals and many output terminals, Especially applicable to a passive optical network (EPON, GPON, BPON, FTTX, FTTH etc.) to connect the MDF and the terminal equipment and to achieve the branching of the optical signal.

The Second,Optical Attenuator. The optical attenuator is a device used to reduce the power level of an optical signal, either in free space or in an optical fiber. The basic types of optical attenuators are fixed, step-wise variable, and continuously variable.Attenuators are commonly used in fiber optic communications, either to test power level margins by temporarily adding a calibrated amount of signal loss, or installed permanently to properly match transmitter and receiver levels.The most commonly used type is female to male plug type fiber optic attenuator, and it has the fiber connector at one side and the other side is a female type fiber optic adapter. The types of fiber optic attenuators are based on the types of connectors and attenuation level. FiberStore supply a lot of fiber optic attenuators, like FC, SC/APC, ST, PC, LC, UPC, MU, FC/APC, SC, LC/APC, fixed value plug type fiber attenuators with different attenuation level, from 1dB to 30dB.

The Third,Fibre Connector. Fibre connector is used to join optical fibers where a connect/disconnect capability is required. The basic connector unit is a connector assembly. A connector assembly consists of an adapter and two connector plugs.Optical fiber connector is removable activities between optical fiber and optical fiber connection device. It is to put the fiber of two surface precision docking, so that the optical output of optical energy to maximize the fiber optic coupler in receiving optical fiber, and optical link due to the intervention and to minimize the effects on the system, this is the basic requirement of fiber optic connector. To a certain extent, fiber optic connector also affects the fiber optic transmission reliability and the performance of the system.

The Fourth,Fiber Optic Transceiver Modules. Fiber optic transceiver is an important device in the optical fiber communication systems, which can be performed between the photoelectric signal conversion, with the receiving and transmitting functions. The fiber optic module is typically composed by the optoelectronic devices, the functional circuit and the optical interface, the optoelectronic device includes a transmitter and receiver in two parts.Usually, it is inserted in devices such as routers or network interface cards which provide one or more transceiver module slot (e.g GBIC, SFP, XFP).

For more information about fiber optic component,pls focus on, we will not regularly updated product, tutorials, blog and other related optical component information.

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.

LC Connector And LC Attenuator

fiber optic connector terminates the end of an optical fiber and enables quicker connection and disconnection than splicing. The fibers are mechanically coupled and aligned to ensure that light can pass.

There has been many different connectors introduced through the development of fiber optic components previously many years. A lot of companies and individuals happen to be trying to improve the options that come with certain connectors to be able to gain control of the fiber optic industry, but only few have been successful. As technology increases, various fiber optic components have become less expensive.

There are various color codes for connectors and they have changed throughout the years. In early stages of fiber optic history, orange, black or grey represented multimode connectors and yellow represented single mode. These original codes became complicated with the introduction of metallic connectors so colored boots were developed, like FC and ST. Now, beige boots stand for multimode, blue means single mode and APC or angled connectors are represented by green boots.

The LC connector is a universal connector. It is available in simplex and duplex configurations and is half how big the SC and utilizes a 1.25mm ferule. The LC is highly favored for single mode and is easily terminated with an adhesive. They’re actively replacing the SC connectors in corporate environments due to their smaller size.

Built on style with LC, LC attenuators really are a combination of a connector on a definite end, as well as an adapter on the other. This enables so that it is “plugged-in” to just about any LC adapter. The assembly contains a ferrule that’s accessible in standard Polish connectors (PC) and 8 degree angle Polish (APC). They’re backward suitable for existing transmission equipment, while the APC attenuators provide superior reflection required for high power and analog equipment. LC fiber optic attenuators are designed to provide horizontal spectral attenuation over the full spectrum vary from 1280nm to 1624nm. This way the LC attenuators expand the capability of optical networks by enabling using the E-band (1400-nm window) for optical transmission.

LC fiber optic attenuator is a passive device accustomed to reduce light signal intensity without significantly changing the waveform itself. It provides a type of metal-ion doped fiber which reduces the noiseless signal because it passes through. This process of attenuation allows for higher performance than fiber splices or fiber offsets or fiber clearance, which function by misdirecting rather than absorbing the joyful signal. This is often a requirement in Dense Wave Division Multiplexing (DWDM) and Erbium Doped Fiber Amplifier (EDFA) applications in which the receiver can’t accept the signal produced by a high-power light source.

LC fiber optic attenuators are key in controlling manipulating the electricity of an optical path in fiber optic telecommunication systems. LC Build-on fiber optic attenuators are used to reduce excess optical power from the transmitter that can result in over-saturation of the receiver.

These optical attenuators feature simple and rugged structure utilizing ion doped fiber because the attenuating material. They can be placed directly on the active equipment and therefore are able to withstand over 1W of extraordinary power light exposure for longer periods of time, which makes them well-suited to EDFA and other high-power applications.

Variable Attenuators Of Fiber Optic Attenuators For Sale From Fiberstore

What is Optical attenuator?

Optical attenuators are used in optical power attenuation device, it is mainly used for fiber optic system of measurement, signal attenuation for short distance communication system and system test, etc. Optical attenuator require light weight, small volume, high precision, good stability, convenient use, etc. It can be divided into fixed, variable, continuous adjustable several classification.

Sometimes in optical network, people need to reduce the fiber optical power levels from one device to another; Fiber optic attenuator is a device, the function. Unit “dB”, normally from 1 dB optical attenuator to 20 dB measures of fiber optic attenuator, fiber optic attenuation level. This is called a fixed value, fiber optic attenuator, each piece of attenuation of optical fiber attenuator is fixed.

Fiber optic attenuators can be designed to use with various kinds of fiber optic connectors. the attenuators can be female to female which is called bulkhead fiber optic attenuator or male to female which is also called a plug fiber optic attenuator. Bulkhead and plug types are designed without cables, another type inline fiber optic attenuator is designed with a piece of fiber optic cable.

Variable Attenuator:

Three basic types of Fiber optical attenuators are step wise variable, continuously variable and fixed.Fiberstore Hot sales fiber optic attenuators are Variable Attenuators. Variable optical attenuator offer a range of attenuation values. They are used for testing and measurement, or when you need to equalize the power between different signals.Variable fiber attenuator can help user vary the light power injected from a light source into the optical fiber. Important parameter of variable fiber attenuator include its insertion loss, reflection loss and attenuation range. We supply ST, FC, SC, LC variable Optical Attenuators with APC, UPC type. Attenuation range available is from 1dB to 30dB.

Wide range variable & inline fiber optic attenuator

The inline fiber optic attenuator are with more accurate attenuation compared with traditional connector type fiber optic attenuators. what is more ,this fiber optic attenuator is with a precision screw set, by turing it ,the attenuation range can be varied. and this fiber optical attenuator can be with various terminations on the each side of the cable.

Fiber optic attenuator technique data

  • UPC type return loss 50dB or greater
  • APC type return loss 60dB or greater
  • Working wavelength 1310nm or 1550nm

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