Optical Switches

In telecommunication, an optical switch is a switch that enables signals in optical fibers or integrated optical circuits (IOCs) to be selectively switched from one circuit to another.

The word applies on several levels. In commercial terms (such as "the telecom optical switch market size") it refers to any piece of circuit switching equipment between fibers. The majority of installed systems in this category actually use electronic switching between fiber transponders. Systems that perform this function by routing light beams are often referred to as "photonic" switches, independent of how the light itself is switched. Away from telecom, an optical switch is the unit that actually switches light between fibers, and a photonic switch is one that does this by exploiting nonlinear material properties to steer light (i.e., to switch wavelengths or signals within a given fiber).

Hence a certain portion of the optical switch market is made up of photonic switches. These will contain within them an optical switch, which will, in some cases, be a photonic switch.

An optical switch may operate by mechanical means, such as physically shifting an optical fiber to drive one or more alternative fibers, or by electro-optic effects, magneto-optic effects, or other methods. Slow optical switches, such as those using moving fibers, may be used for alternate routing of an optical switch transmission path, such as routing around a fault. Fast optical switches, such as those using electro-optic or magneto-optic effects, may be used to perform logic operations; also included in this category are semiconductor optical amplifiers, which are optoelectronic devices that can be used as optical switches and be integrated with discrete or integrated microelectronic circuits.

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