Fiber laser based hydrophone systems

Abstract

We report our recent work on distributed feedback fiber laser based hydrophones. Some issues related to sensitivity, such as fiber laser phase condition, demodulation, and packaging, are also discussed. With the development of appropriate digital signal processing (DSP) techniques and packaging designs, an interferometric-type distributed feedback (DFB) fiber laser hydrophone system with acoustic sensitivity of 58.0 dB·re·μPa·Hz −0.5 at 1 kHz or a minimum detectable acoustic pressure below 800 μPa during field test is attained. We have also investigated an intensity-type DFB fiber laser hydrophone system and its performance.

Compensation of output signal temperature dependence in homodyne demodulation technique for phase fiber-optic sensors

“…Он по-лучил широкое распространение благодаря двум своим особенностям: метод не требует использования петли обратной связи, а выходной сигнал схемы обработки не зависит от положения рабочей точки ин-терферометра [4]. В последнее время этот метод был усовершенствован схемой на основе вычисления арктангенса [5].…”

Experimental investigations on implementing different PGC algorithms for interrogation of fiber optic hydrophones

“…Various methods were adopted for it over this period viz. active homodyne, passive homodyne, pseudo heterodyne and synthetic heterodyne and a comprehensive comparison among them is given in ref [5]. Among all, passive homodyne with Phase Generated Carrier (PGC) is the most widely used scheme for fiber optic hydrophones for its superiorities viz.…”

A four-element sensor array consisting of asymmetric distributed-feedback fiber lasers

“…In recent years, many attractive features of distributed-feedback fiber laser (DFB-FL) have been reported with regard to their applications in sensing systems [1][2][3][4]. The DFB-FL exhibits great advantages including the small size, simplicity, extremely high sensitivity, intrinsically narrow emission line width, robust signal mode operation, remote pumping, and inherent high multiplexing capability.…”