British Telecommunications Public Limited Company

British Telecommunications Corporation

Corning Incorporated

The Post Office

Roderick Peter Webb

Peter Healey

David W Smith

Alistair James Poustie

David Charles Wood

Robert John Manning

Raymond C Hooper

Edward G Scott

Marek A Rejman-Greene

Alan W O'Neil

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. Relative phase offsets are induced at the outputs of the two interferometers of the regenerator to obtain either minimum transmission from each of the interferometers by the maximum power levels of the respective input signals transmitted therethrough, or maximum transmission from the interferometer of the first stage by the maximum power level of the data signal, and minimum transmission from the interferometer of the second stage by the minimum power level of the output from the first stage of the regenerator.

Optical regenerator

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.

Telecommunications switch

Optical interconnect

Sagnac loop interferometer

Neural networks

Optical signal regenerator and optical communications system

Bistable optically clocked optical signal regenerator

Optically controlled selector

Optical communication system utilizing phase modulation

Optical coupling assembly

A signal level stabilizer includes two amplifier stages, each stage having a respective feed-back loop to control its gain. The gains of the amplifiers are varied in response to variations in the level of the input signal to give a substantially constant output signal. At low levels of the input signal the gain of one of the amplifiers only is varied in response to variations of the input signal and at high levels of the input signal the gain of the other amplifier is varied. The amplifiers may be part of a repeater in an optical communications linkage and one of the amplifiers may then be a photodiode and the other a power amplifier.

Signal level stabilizer

Growing community of inventors

Woodbridge, United Kingdom

Roderick Peter Webb