Abstract

The ability to make in miniature basic optical components is one of the most important factors in the development of intergrated optics circuit. Recently, fabrication of extremely compact components, such as beam splitters¹ and zero-gap directional couplers,² have been realized. These devices require interaction lengths of only a fraction of a millimeter to perform their required functions. The miniature beam splitter¹ consists of two perpendicular AlGaAs/GaAs ridge waveguides, with a groove at the intersection. The groove was milled with a microfocused ion beam, and it was reported that the beam-splitting ratio could be adjusted by varying the groove depth. This device could be used as a power splitter or coupler or in the DFB laser circuit. The simple geometry permits easy integration, and a network of such structures may find application in optical computing. In this paper the beam-splitting characteristics of two perpendicular waveguides containing a 45° gap at the intersection, as shown in Fig. 1, are simulated by the FDTD method.³ Simulated results of the splitting ratio as functions of wavelength, gap width, and index change in the gap are presented.

© 1990 Optical Society of America