Interferometer for detecting optical wavelength variations - has waveguides providing measuring arm and 2 reference arms of differing optical wavelength

摘要

The interferometer for detecting optical wavelength variations uses a monochromatic laser light source coupled to a beam splitter for providing measuring and reference beams. The light is fed to the beam splitter and fed back to photodetectors via waveguides formed on a substrate (1) to provide a single measuring arm (7) and 2 reference arms (6,8) with different optical wavelengths providing a phase difference. The photodetectors are coupled to an electronic evaluation stage, for determining the variation in the optical wavelength of the measuring arm (7). Pref. thermooptical, or electrooptical phase modulators operated by a DC signal are associated with the measuring arm (7) and one of the 2 reference arms (6,8). ADVANTAGE - Increased resolution.