Transparent low-loss N × N optoelectronic switch fabric

Abstract

There is considerable interest worldwide in reconfigurable, transparent switch fabrics with low loss for both telecom and computing applications. A number of architectures employing liquid crystal devices have been suggested for switches where reconfiguration times of µsec to 1 sec are acceptable [1]. These-are either multistage, with control and latency overheads, or single stage, such as the matrix-vector multiplier approach with 1/N2 loss (N being the number on input and output channels). An alternative single stage scheme, where a computer generated hologram is written on the SLM [2,3], charges the latter with the task of control and beam shaping. The use of multi-focus diffractive optical elements to direct the beam, which would relieve the charge on the LCTV and improve the throughput efficiency, has been proposed recently [4]. However, the results on the basic system show low throughput efficiency and unacceptable crosstalk, A high throughput efficiency is required for an acceptable bit error rate on a high speed link. The principle of a low-loss link based on free space optics is described in this paper.