British Telecommunications Public Limited Company

British Telecommunications Corporation

Nicholas J Doran

Keith J Blow

Brian P Nelson

David Cotter

David Charles Wood

Keith James Blown

Bimal K Nayar

An optical communications system comprises a laser (,) controlled to output a stream of soliton pulses (,) coupled to a beamsplitter arrangement (,) which converts the pulse stream (,) to a stream of pulses (,) having twice the pulse rate. This stream of pulses (,) is modulated to form a binary coded signal by modulator (,) as a series of binary digits each having one of two values in which a series of n optical soliton pulses, where n is an integer>1 is coupled into an optical fibre (,) at each occurrence of one of the two values. The optical fibre (,) and repeaters (,) provide a transmission link to a receiver (,). The present invention allows one to increase the average power within a bit without having to operate with shorter pulses that would otherwise be necessary with one soliton pulse per bit of prior art systems in order to avoid the limits inherent in single soliton pulse per bit prior art systems. The result is that the ASE noise limit is moved to longer pulses so allowing higher bit rates notwithstanding that there is a greater number of solitons in each bit of data than with single soliton per bit scheme of modulation. The method also reduces GH the jitter and thus opens the window of operation by pushing the G-H limit to longer pulses

Method and apparatus for transmitting information

Optically controlled optical switch

Quantum non-demolition optical tapping

Optical domain digital pulse switching

Square optical pulse generator

An optical fibre, loop interferometer (31) is formed from germania doped silica which exhibits Raman scattering at a threshold intensity to provide a transmitted optical signal from port (49) of coupler (35) whose intensity is a sigmoid function of the intensity of an optical signal input at port (39). It finds application in optical switching and logic operations on optical pulses.

Non-linear inferferometer

Optical nonlinear cross-coupled interferometer and method utilizing same

Optical device producing an intensity dependent phase shift

Apparatus and methods for processing optical signal with waveguides

Growing community of inventors

Cambridge, United Kingdom

Nicholas J Doran