Fibre=optic hydrophone with multi pick=up antenna - has super-luminescent diode source with integrated optical commutator and fibre coil of FASE structure

摘要

The hydrophone has an antenna and a source (S) with a wide spectrum and weak coherence using a coupled monomode fibre (30). It is also possible to use a luminescent diode or a laser. The source is modulated between two pick-ups and a recurrence at the top wall. The source is controlled by processing circuits (40) through a command signal (400). The emitted signals use integrated optics (31) using a polariser (310), a controllable optical delay (311) and a phase modulator (312). The polariser is for rectilinear wave polarisation and is transmitted by the fibre (30). The elements under the control of the signal (401) issued by the processing circuits creates two waves with time-variable delay. The optical fibres can be replaced by waveguides. Temporal staggering is introduced to compensate for the delay in the wave propagation in the fibres of the FASE type. The phase modulator (312) modulates the phase of the two waves through the circuit (313) and a control signal (402) and is coupled to an optical amplifier (32). ADVANTAGE - Minimises number of wires/fibres for connecting pick-ups along antenna.