An interferometer is an important optical instrument for measuring the distribution of index and thickness of a medium or the displacement of an object with very high sensitivity. We present an active interferometer in which the optical phase signal of the interferometer is fed back to the frequency of a light source. A single-mode laser diode is used for the light source. This active interferometer is very simple but can be used for many purposes, e.g., for the stabilization of an interferometer, for the displacement measurement.
© 1984 Optical Society of AmericaPDF Article