Switching is an essential operation in communication networks. It is also a basic operation in digital computers and signal processing systems. The current rapid development of high-data-rate fiber-optic communication systems has created a need
for high-capacity repeaters and terminal systems for processing optical signals and,therefore, a need for high-speed photonic switches. Similarly, the potential for optical computing can only be realized if large arrays of fast photonic gates, switches, and memory elements are developed