INTERFEROMETRIC DETECTION SCHEME FOR MEASURING WAVELENGTH SHIFT USINGA STABILIZED INTERFEROMETER WITH AN ADDITIONAL REFERENCE WAVELENGTH

A novel interferometric detection scheme for measuring wavelength shif t, with applications to optical sensing systems is described. In this scheme, in addition to the source wavelength to be measured, a further reference wavelength is employed to stabilize the optical path differ ence of the interferometer. This is designed to make the wavelength de tection system insensitive to environmental disturbances such as tempe rature fluctuations and mechanical vibration, and using this scheme a signal-to-noise ratio improvement of similar to 25 dB has been shown i n a demonstration system.