Mach-Zehnder Type Tandem Optical Switch/Modulator using a Single-Mode Interconnecting Waveguide and Its Switching Characteristics

In this paper, an optical switch/modulator is designed and its light propagating characteristics analyzed using a simplified BPM. The distinctive feature of this switch/modulator is that all its waveguide branches are designed as single-mode. The principle of the device is based on the coupled mode theory in the Y-junction interconnecting waveguide. In spite of the fact all waveguides are designed as single-mode, by adjusting the interconnecting waveguide length'of the device the same characteristics as existing up to date devices are obtainable. Numerical results show that the switching characteristics periodically depend upon an interconnecting waveguide length with a spatial of about <TEX>150^μm</TEX> in the <TEX>Ti:LiNbO₃</TEX> step index waveguide. The design concept would therefore be utilized effectively in fabricating a monolithic high density optical integrated circuit.