OPTICAL FILTER

摘要

A fiber optic tapped delay line is disclosed in which a number of bends in a single optical fiber are formed to obtain taps of an optical signal traveling in that fiber at each bend location. Light removed at the bends is directed to a focusing lens, which focuses the light onto a photodetector acting as a summing device to produce a frequency-filtered output of the light signal traveling in the fiber. The device's response as a transversal filter is enhanced by weighting the taps either by use of a cylindrical lens, or by selectively masking a portion of light emitted by selected individual taps.