Planar optical waveguide, modulator, variable coupler and switch

摘要

A planar semiconductor optical waveguide, modulator, variable coupler and switch are described. The waveguide has an epitaxial layer on a semiconductor substrate. Two spaced strips of opposite conductivity type are implanted in the layer to form an optical waveguide channel in the space. By closely spacing two waveguide channels so that they have a common strip and a strip outside each channel, coupling is obtained between the channels. For a switch, the coupling length is such that substantially all the optical energy in the input channel is coupled to and emerges from the other channel. Reverse biasing one of the outside strips causes the optical energy to divide between the input channel and the output channel to provide output power modulation or variable coupling, and substantially complete transfer of power (switching) for a particular value of reverse bias.