What is a Fiber Optic Attenuator and what is it used for?

by http://www.fiber-mart.com

The Fiber Optic Networks are the fastest networks today. They provide high bandwidth, long distance, reliable network solution. The two main components of a stable Fiber Optic Network are optical transceivers and optical cables. The whole solution is based on an electrical signal converted into optical light and then being transmitted by the optical transceiver down an optical cable. This light travels down the cable through one or multiple optical fiber strands. Depending on the type of transceivers and cables, the bandwidth and distance of the connection may vary.
The ability of the optical transceivers to transmit the optical light down the cable depends on their optical power. One major characteristic of the optical power of transceivers is the optical data link bit error rate. Having too much, or too little power can result in high data link bit error rates causing an intermittent connection. When having too little power the noise inside the cable is starting to become a problem because it interferes with the optical light. Having too much power will cause the receiver amplifier to saturate beyond the limit. This is mainly happening in Single-mode systems with laser transmitters. This is known as optical fiber attenuation. Optical fiber attenuation refers to the loss of optical energy of the optical light which happens while the optical light travels through the cable.
Generally only Single-mode systems, and short distance particular, have the need for attenuators. Multi-mode attenuators don’t have the need for attenuators because their transmitters, even VCSELS, don’t have enough power to saturate receivers.
In the past when people ran into these kinds of problems their solution was to wrap the cable around a round object like a pen, until the power is evened out and the desired attenuation is met. However, as the fiber optic cable is subjected to various stress including banding, today we can easily avoid these problems with the help of the Fiber Optic Attenuator. The Fiber Optic Attenuator is a device that is used to lower down the optical power so the receiver doesn’t get saturated. In today’s attenuators the reducing of power is mostly done by absorbing the extra optical light. Today’s attenuators are ultra-precise in reducing the power to a fixed or adjustable amount. They are also used for testing of the dynamic range of photo sensors and detectors.
Fiber Optic Attenuators exist in various shapes and sizes, however the most known and used are:
Fixed Power Attenuators- These attenuators are a compact size attenuators designed to reduce the power to a certain amount. As the signal approaches the communication device the power of the signal is reduced. Because of the way they function they are reducing the signal reflection effect and provide a more accurate transmission of the data. These attenuators are available with either multi-mode or single-mode fibers. They are mainly used for single-mode solutions in the LAN, CATV and Service Providers.
Variable Power Attenuators- These attenuators are slightly bigger than the fixed attenuators. They are mainly used for testing or equalizing the power between two signals. Unlike the fixed attenuators, these attenuators can offer a wider range of adjustable power values. Their main function consists of directly blocking the optical light and as a consequence they are insensitive to polarization. They are also available for multi-mode and single-mode fibers.
All BlueOptics© Attenuators are developed for ultra-sensitive power adjustments. They are available with different connectors: LC-APC (SFA21BAXX), LC-PC (SFA21BKXX for Single-mode and, SFA21EKXX for Multi-mode) SC-PC (SFA22BKXX), SC-APC (SFA22BAXX) and ST-PC (SFA23BKXX). All BlueOptics© Attenuators have a ceramic ferrule guaranteeing the best attenuation values and working in temperatures between -40°C and +75°C. All BlueOptics© Attenuators are manufactured by the leading manufacturers for connectors like Amphenol, Diamond and Nissin Kasei. All BlueOptics© Attenuators are tested after their manufacturing process with a highly precise interferometer and Optical-Time-Domain-Reflectometry to ensure only the highest quality attenuators are offered on the market. All BlueOptics© Attenuators are standardized and they all meet the IEC-61034, IEC-754-1, IEC 60332-1, IEC 60332-3, IEC/EN 60950 and RoHS standards. They offer a lifetime of 1500 mating cycles, 25 years warranty and a lifetime support.