What does an Optical Attenuator do

Posted on by FS.COM

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.

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March 2017
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