Abstract: There is provided a two-stage optical regenerator for regenerating a data signal comprising a series of optical pulses. Each stage of the optical regenerator comprises a modulator for modulating a reference signal with an input signal, and an interferometer for causing the modulated reference signal to interfere with another version of the modulated reference signal delayed by less than one bit period of the data signal to regenerate the input signal. The input signal of the modulator of the first stage of the regenerator comprises the data signal, and the input signal of the modulator of the second stage of the regenerator comprises the output from the first stage of the regenerator.

Abstract: There is provided a two-stage optical regenerator for regenerating a data signal comprising a series of optical pulses. Each stage of the optical regenerator comprises a modulator for modulating a reference signal with an input signal, and an interferometer for causing the modulated reference signal to interfere with another version of the modulated reference signal delayed by less than one bit period of the data signal to regenerate the input signal. The input signal of the modulator of the first stage of the regenerator comprises the data signal, and the input signal of the modulator of the second stage of the regenerator comprises the output from the first stage of the regenerator.

Abstract: A self-routing switch such as a Banyan switch has a controller which recognizes incoming routing requests which would give rise to blocking in the switch and makes and optimum selection of queued requests which can be handled without blocking. The controller is implemented by means of an optical neural network having a light source array to illuminate a photodetector array through a mask, there being a light source array element and a photodetector element for each possible path through the switch. The assignment of paths to array locations is such that, for the path corresponding to any light source array element, the photodetector array element positions corresponding to the paths blocked thereby form a pattern which is a shifted version of the pattern formed by the photodetector array elements corresponding to the paths blocked by a path corresponding to any other light source array element, whereby a single mask may be employed.