Integrated optics for displacement sensors

The use of integrated optical components can be highly beneficial in the realization of displacement sensors. To affront efficiently the problems related with fringe counting and signal fading, the configuration of the optical interferometer is particularly important. Passive interferometer configurations are preferred, with the phase shifted output signals being directly available optically, since they allow a simplified electronic processing for fringe counting and phase demodulation. This article reviews the contributions integrated optics can make in the realization of efficient, compact and reliable displacement sensors. Special emphasis is made in comparing passive interferometer configurations to obtain the phase diversity. The different possibilities in the realization and integration of the optical, optoelectronical and electronical elements are mentioned.