Abstract: Some embodiments are directed to a multiplexed fiber sensor for a fiber optic hydrophone array, including a signal receiver configured to receive a signal from the fiber optic hydrophone sensor array and an interferometer. The interferometer is configured to produce a first signal component and a second signal component from the signal received from the hydrophone array, and also provided with a first polarization controller configured to control the polarization of the first signal component and a second polarization controller configured to control the polarization of the second signal component. A modulated carrier signal generator configured to generate a modulated carrier signal component based on the first signal component is also provided. A detector configured to output a demodulated output signal from the modulated signal component and the second signal component is included, wherein the modulated signal component and the second signal component output separately from the interferometer.

Abstract: Some embodiments are directed to a multiplexed fiber sensor for a fiber optic hydrophone array, including a signal receiver configured to receive a signal from the fiber optic hydrophone sensor array and an interferometer. The interferometer is configured to produce a first signal component and a second signal component from the signal received from the hydrophone array, and also provided with a first polarisation controller configured to control the polarisation of the first signal component and a second polarisation controller configured to control the polarisation of the second signal component. A modulated carrier signal generator configured to generate a modulated carrier signal component based on the first signal component is also provided. A detector configured to output a demodulated output signal from the modulated signal component and the second signal component is included, wherein the modulated signal component and the second signal component output separately from the interferometer.

Abstract: Apparatus (100) is provided which is arranged to accept an input data stream. In some embodiments, the apparatus (100) comprises a sampler arranged to sample the input data stream to provide k samples thereof, wherein each of the samples is n bits long and a string selector arranged to select m binary strings n bits long from at least a chosen subset of all random binary strings of a predetermined length. The apparatus (100) may further comprise a logical operator arranged to perform a logical function for each of the k samples with each of the selected binary strings to provide a vector, a memory arranged to store a matrix of the vectors generated from k samples, and an address generator arranged to generate RAM address segments from the matrix. In embodiments, the apparatus (100) may comprise a processor for, for example, pattern matching; feature detection, image recognition.

Abstract: Apparatus (100) is provided which is arranged to accept an input data stream. In some embodiments, the apparatus (100) comprises a sampler arranged to sample the input data stream to provide k samples thereof, wherein each of the samples is n bits long and a string selector arranged to select m binary strings n bits long from at least a chosen subset of all random binary strings of a predetermined length. The apparatus (100) may further comprise a logical operator arranged to perform a logical function for each of the k samples with each of the selected binary strings to provide a vector, a memory arranged to store a matrix of the vectors generated from k samples, and an address generator arranged to generate RAM address segments from the matrix. In embodiments, the apparatus (100) may comprise a processor for, for example, pattern matching; feature detection, image recognition.

Abstract: An optical correlation apparatus is described which forms first and second parallel optical signals in response to a serial input data stream. The first parallel optical signal is arranged to have bright pulses represent binary 1 and the second parallel optical signal is arranged to have bright pulses represent binary 0. A channel select means, such as an optical switch or amplitude modulator, deselects or blocks channels in the first parallel optical signal which correspond to binary 1 in a reference data string and also deselects or blocks channels in the second parallel optical signal which correspond to binary 0 in the reference data string. The remaining optical signals are combined at one or more detectors. Where the input data matches the reference data string each bright pulse in the first and second parallel optical signals is deselected and the detector registers zero intensity. However when there is any mismatch at least one channel will pass a bright pulse to the detector.

Abstract: An optical correlation apparatus is described which forms first and second parallel optical signals in response to a serial input data stream. The first parallel optical signal is arranged to have bright pulses represent binary 1 and the second parallel optical signal is arranged to have bright pulses represent binary 0. A channel select means, such as an optical switch or amplitude modulators deselects or blocks channels in the first parallel optical signal which correspond to binary 1 in a reference data string and also deselects or blocks channels in the second parallel optical signal which correspond to binary 0 in the reference data string. The remaining optical signals are combined at one or more detectors. Where the input data matches the reference data string each bright pulse in the first and second parallel optical signals is deselected and the detector registers zero intensity. However when there is any mismatch at least one channel will pass a bright pulse to the detector.