All-optical processing in communications systems

An optical processing system for converting an input optical data signal comprising a plurality a discrete wavelength square wave data channels to an output optical data signal comprising a single wavelength time division multiplexed pulsed signal, said system comprising:

• a first non-linear optical device arranged to receive the input signal and a first clock signal and to provide an output optical pulsed signal representation of the original square wave signal, said input signal comprising a plurality of discrete wavelength square wave data channels having a relatively low optical power and said clock signal comprising a pulse train having a frequency at least as high as the highest data rate data channel and a relatively high optical power;
• means to temporally disperse the different wavelength components of the output optical signal by respective pre-determined amounts to provide a wavelength-interleaved output optical pulsed signal;
• and
• a second non-linear optical device arranged to receive the resultant output optical pulsed signal and a second clock signal, and to provide a single-wavelength output optical pulsed signal, said input signal having a relatively low optical power and said clock signal comprising a pulse train having a frequency substantially equal to that of the pulsed signal and a relatively high optical power.

A method of producing a multiple channel pulsed data signal from a multiple channel square wave data signal, said method comprising the steps of:

• introducing a multiple channel square wave data signal into a non-linear optical device;
• introducing a pulsed clock signal having a repetition frequency at least as high as the highest data rate square wave data channel into the device;
• and
• arranging the respective signal power levels to provide an output data signal including perturbed data signal portions resulting from cross phase modulation of the data and clock signals, said perturbed data signal portions corresponding to a pulsed signal representation of the square wave data channels.