Dual-wavelenth passive homodyne detection unit for fiber-coupled white-light interferometers

Michel Lequime, Catherine Lecot, Hugues Giovannini, Serge J. Huard, Ralf T. Kersten
1990 Fiber Optic Sensors IV  
This paper is devoted to the description of a prototype Emission/Detection Unit, the ACCORD® Module, developed for the accurate demodulation of fiber optic sensors using spectral modulation encoding techniques. This prototype contains a static polarimetric interferometer with 4 ports to provide the four phase signals needed by the passive homodyne scheme, and uses a dual-wavelength arrangement to extend the measurement range by removing the 2ic ambiguity in the phase determination. Resolution
more » ... ation. Resolution as high as A/40000 has been achieved with 1 Hz bandwith and Optical Path Difference mismatch in a 20 microns range.
doi:10.1117/12.20316 fatcat:wzmvcdw5yfhclfoz77ksjlckti