INTERFERENCE OPTICAL SWITCH AND VARIABLE OPTICAL ATTENUATOR

摘要

An interference optical switch capable of switching in a wide band, having a high extension ratio and produced with a large production tolerance and an optical switch module. As optical multiplexing/demultiplexing means, a phase generation coupler (111) the output of which involves a phase difference having wavelength dependence is used. The total sum 2.pi.{.phi.1(.lambda.)+.phi..DELTA.L(.lambda.)+.phi.2(.lambda.)} of the phas e difference .phi.1(.lambda.) of the light outputted from the phase generation coupler (111), the phase difference .phi..DELTA.L(.lambda.) due to the optic al path length difference of an optical path length difference imparting sectio n (131), and the phase difference.phi.2(.lambda.) of the light outputted from a directional coupler (153) is constant independently of wavelength. Thus, an interference optical switch independent of wavelength is realized.