Polarization-selective phase modulator: a potential component for interferometric fiber optical sensors?

This paper discusses the potential use of polarisation selective phase modulators, PSPM, in interferometric fiber optical sensors. The principle of the PSPM is shortly reviewed. Two examples of the usefulness ofpolarisation selective phase modulation will be given. The first showing that PSPM introduces a possibility to monitor two measurands, simultaneously, with the same interferometer. In the second, a more detailed look at the consequences of using this concept in fiber optical gyros wiibe presented. A formula is derived describing the suppression ofnoise due to polarisation coupling in the gyro fiber loop. Using a special modulation and detection scheme, the PSPM shows to reduce the noise with the same order of magnitude as a polarizer.