The Commonwealth of Australia

Thales Underwater Systems Pty Limited

Thales Australia Limited

Scott Foster

Alexei Tikhomirov

Ian Bedwell

John Van Velzen

Francois Luc

A fiber optic sensor arrangement is disclosed that includes a plurality of optical fiber based sensor elements, the sensor elements configured to modify an associated optical carrier signal in accordance with changes in a sensed quantity at a location of the sensor element and a phase modulation arrangement for phase modulating each optical carrier signal in accordance with respective uncorrelated pseudorandom binary sequence signals. The sensor arrangement also includes an interferometer module for receiving each of the phase modulated optical carrier signals, the interferometer module operable to convert a change in the phase modulated optical carrier signals to a change in optical intensity of the corresponding optical carrier signal to generate a combined modulated optical intensity signal, an optical intensity detector for measuring the combined modulated optical intensity signal and generating a time varying electrical detector signal and an analog to digital convertor to convert the time varying electrical detector signal to a time varying digitized detector signal. Also included in the sensor arrangement is a decorrelator arrangement for decorrelating the time varying digitized detector signal against the respective uncorrelated pseudorandom binary sequence corresponding to each of the optical carrier signals to recover each of the modulated optical carrier signals and a demodulator for demodulating each of the modulated optical carrier signals to recover the respective optical carrier signal to determine the changes in the sensed quantity at the location of the sensor element.

Sensor arrangement

A device () for sensing an acoustic signal is described. The device includes a flexible portion () including a laser active region () whose emitted wavelength varies according to a mechanical force acting on the flexible portion () and a flexible support member () operable to flex or bend according to the acoustic signal. The flexible portion () is coupled with the support member () so as to cause the flexible portion to flex or bend in accordance with the support member () thereby changing the emitted wavelength of the laser active region () of the flexible portion ().

Opto-acoustic pressure sensor

A method and apparatus for modifying the out of band reflection of a laser element is described. The laser element includes an active medium excited by optical pumping means to produce stimulation emission of light. The laser element further includes a Bragg grating structure for providing optical feedback for the active medium, with the Bragg grating structure including a phase transition region providing a change in phase. The change in phase of the phase transition region is adjusted to modify out of band reflection of said laser element.

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Edinburgh, Australia

Scott Foster