Abstract

Monolithic integrated optics based on an InGaAsP/lnP system is receiving increasing attention for applications in large-capacity and long-distance optical communication systems in the 1.3-1.6-/um wavelength. In this field, InGaAsP/lnP electrooptic directional-coupler optical modulators/switches appear to be particularly attractive, because they can be integrated with active devices such as double-heterostructure laser diodes (DH LB) or photo- diodes and, therefore, have a good possibility of obtaining a wide variety of uses. One promising application of this type of optical modulator/switch is an external modulator monolithically integrated with DH LDs, which will be free from the dynamic wavelength fluctuations of LDs under high-speed direct modulation. For this application, a modulator with DH waveguides is suitable because of the similarity of both waveguide structures. The recently demonstrated homojunction structure mod- ulator¹ seemed to have some disadvantages in this respect. This paper presents an optical modulator with InGaAsP/lnP DH waveguides, which is suitable for monolithic integration with DH LDs.

© 1983 Optical Society of America