Integrated optical light coupling device with reduced losses - has expansion horns on ends of transmission and return optical waveguides for monomode signal, and planar reflector directing signal from transmission guide to return guide

摘要

The integrated optical coupler, for permitting a monomode optical signal to propagate via a leading or transmission waveguide (2) towards a return guide (7), has expansion horns (3,6) on the ends of the transmission and return guides, respectively, at the junction of the coupling. A planar reflector (5) is located a distance d from the horns, which are oriented at an angle alpha to the normal to direct an optical signal from the transmission horn to the return horn. The waveguides support monomode signal propagation with lateral confinement. the reflector comprises a mirror arranged on a substrate, or a back-coupling network. ADVANTAGE - Avoids reflection back into transmission waveguide. Reduced optical attenuation, by increasing difference index delta-n between guide and gain, and by increasing thickness of waveguide or fibre without risk of multimode operation.