ULTRA-FAST TUNABLE OPTICAL FILTERS

摘要

A fast interferometric tunable optical filter consists of a variable delay line, with a fast phase modulator (10) inserted into the line, which acts as a resonator loop (8, 43) and is connected between the ports of an optical coupler (6, 14). The filter provides tuning speeds of the order of one nanosecond, making the filter suitable for use in selecting a desired wavelength division multiplexed signal as used in optical communications systems. The filter can be implemented in single resonator form, or, to provide improved performance, in a compound resonator form. It can also be constructed in fiber optical form (24, 25), or in a monolithic form on a chip of gallium arsenide in an integrated optics configuration, thereby providing lower production costs and improved performance.