OPTICAL MODULATOR

摘要

An optical modulator for duobinary modulation is based on a Mach-Zehnder interferometer but has parallel optical waveguides of a greater length than normally is employed with an optical modulator. A pair of similar electrode structures are arranged in series on the waveguides, the electrodes of the two structures being separately addressable by binary electrical signals. The phase shifts induced in the light propagating along the parallel waveguides by voltages applied to the separate electrode structures allows the output to take values of 0, 1 or 2 for binary inputs applied to the structures.