COMPARISON OF PROPAGATION LOSSES OF SINGLE-MODE GAAS/ALGAAS WAVE-GUIDES IN A 3-LAYER AND 5-LAYER STRUCTURE

Abstract

Single-mode GaAs/AlGaAs ridge waveguides with a three- and a five-layer heterostructure have been designed using an effective index method and fabricated using a metalorganic chemical vapor deposition (MOCVD) technique and the chemical wet etching method. The propagation loss was measured by the Fabry-Perot resonance method and sequential cleaving experiment at 1.31 mu m wavelength. The propagation loss is as low as 0.62 dB/cm for waveguides with a double heterostructure. For five-layer waveguides with a W-shaped index profile, it is 0.23 dB/cm, comparable to the lowest loss value of semiconductor waveguides yet reported. Therefore the W-type waveguides provide a useful basis for low-loss guided-wave devices for integrated optoelectronics.