Optical TDM switch architectures

The authors propose some designs for optoelectronic TDM switches that use Ferroelectric Liquid Crystal (FELC) devices. These are capable of switching speeds of the microsecond order and lends itself admirably to very high orders of parallelism. Ferroelectric liquid crystal technology with an active silicon VLSI back plane (FELC/VLSI) is well suited to the production of high density interconnects based on integrated `smart pixels´. It is suggested that these properties may be helpful for packet and/or circuit switching in telecommunication networks where there is a need to switch many thousands of circuits in parallel. The wide dynamic range of electro-optic effects in FELCs enables high fan-outs to be achieved and FELC/VLSI technology results in costs that are not critically dependent on the number of crosspoints in the switch. This means that relatively simple single-stage switching structures can be used compared with the multi-stage switching arrangements that are the norm when crosspoint costs are dominant or when fan-out is limited