Abstract: A system for estimating values of a vector of variables that optimize a function comprising a weighted sum of interactions between the variables; the system comprising a plurality of parallel hardware channels, each arranged to model a contribution of a respective variable to the function, each channel comprising: a signal generator configured to generate a signal modelling a value of the respective variable; a splitter arranged to supply the signal to each of the channels; interaction logic configured to multiply the vector of signals by a vector of weights modelling an interaction between the respective variable and the vector of variables, thereby generating a feedback signal representing the contribution of the respective variable; and a feedback path to return the feedback signal to the signal generator configured to adapt the signal in dependence on the feedback signal, wherein each channel is implemented only using optical components and/or analogue electronic components.

Abstract: An optical regenerator for regenerating a multi-level phase encoded signal. A first non-linear medium (HNLF1) generates a comb of frequency harmonics from the signal under the action of a coherent pump, each component bearing the phase encoded data. A filter selects the first and (M?1)th order components. The filtered signal is then input to a second non-linear medium (HNLF2) where a further pump is applied, to coherently add the first and (M?1)th order components and regenerate the signal by reducing phase noise.

Abstract: An optical device, suitable for use either as a coherent receiver or analog-to-digital converter, of optical phase modulated signals borne on a carrier. The signal is four-wave mixed with a pump to generate a non-linear comb of a series of harmonic components of the signal. The modulation-free carrier is also combined with the pump to generate an equivalent linear comb matched in frequency to the components of the non-linear comb. The harmonic and modulation-free components are linearly combined so they interfere in a pairwise manner, and then the interfered frequency components are separated out in an optical wavelength division demultiplexer into a plurality of frequency-specific optical output channels. A plurality of photodetectors connected to respective ones of the optical output channels then converts the analog values in each channel to respective electronic signals which are then digitized using a processor into binary digits using a thresholding process.

Abstract: An optical regenerator for regenerating a multi-level phase encoded signal. A first non-linear medium (HNLF1) generates a comb of frequency harmonics from the signal under the action of a coherent pump, each component bearing the phase encoded data. A filter selects the first and (M?1)th order components. The filtered signal is then input to a second non-linear medium (HNLF2) where a further pump is applied, to coherently add the first and (M?1)th order components and regenerate the signal by reducing phase noise.