FIBRE-OPTICAL INTERFEROMETER Russian patent published in 1997 - IPC

FIELD: technical physics, hydrology, underwater acoustics to measure parameters of underwater acoustic and hydrophysical fields. SUBSTANCE: fibre-optical interferometer has signal and reference fibre coils optically matched with source of coherent light and photodetector. Part of reference coil is wound on surface of piezoelectric element linked to generator of saw-tooth pulses. Measurements with the aid of interferometer are conducted at moments of change of optical path in reference coil by linear law when carrier Doppler frequency 50-60 MHz is present across output of photodetector even in absence of input signal. Under action of input signal in signal coil with frequency not exceeding 10 kHz frequency modulation of carrier frequency takes place which allows level of input signal to be measured after discrimination in frequency discriminator. EFFECT: expanded application field and improved functional reliability. 2 dwg