B-ISDN waits for photonics to deliver

A variety of photonic switching techniques have been studied from the viewpoint of expanding switching-mode throughput. The basic issue discussed is how the high bandwidths of optical devices can be applied to switching nodes. It is shown that a high time-domain bandwidth allows high-speed signal transmission without waveform distortion, a high frequency-domain bandwidth allows a system to accommodate a large number of channels, which results in a high-capacity system, and a high space-domain bandwidth allows high-density interconnections in free space and resolves the pin-out bottleneck of LSIs and multichip modules (MCMs). Photonic space-division switching, photonic ATM switching, photonic frequency-division switching, and photonic free-space switching methods are described