Fiber optic attenuators are devices that reduce signal power in fiber optic links by inducing a fixed or variable loss. They are used to control the power level of optical signals at the outputs of light sources and electrical-to-optical (E/O) converters. They are also used to test the linearity and dynamic range of photo sensors and photo detectors.
Fiber optic couplers are optical devices that connect three or more fiber ends, dividing one input between two or more outputs, or combining two or more inputs into one output.
Optical isolators are optical devices that allow light to be transmitted in only one direction. They are most often used to prevent any light from reflecting back down the fiber, as this light would enter the source and cause feedback problems.
Specialty optical fiber is modified, usually by doping, for a specialized function. It consists of one or more transparent fibers enclosed in a protective covering.
Wavelength division multiplexers (WDM) are passive devices that combine light signals with different wavelengths, coming from different fibers, onto a single fiber. They include dense wavelength division multiplexers (DWDM), devices that use optical (analog) multiplexing techniques to increase the carrying capacity of fiber networks beyond levels that can be accomplished via time division multiplexing (TDM).
