LINEAR-PHASE TRACKING IN A COHERENCE MODULATION ELECTRICAL SENSOR SYSTEM USING INTEGRATED LINBO3 MODULATOR DEMODULATOR/

We report an interferometric sensor system, based on coherence modulat ion of light and LiNbO3 integrated optics technology, We describe a ph ase detection scheme designed to retrieve the absolute phase variation s produced by a sensor system where the sensor signal is electronicall y applied to an electro-optic modulator, The system consists of an imb alanced LiNbO3 Mach-Zehnder transducer fed by a self-powered charge ge nerating sensor, and an optoelectronic central processing unit includi ng a second electrooptic Mach-Zehnder working as an optical demodulato r and featuring a matched path-imbalance, Electrical feedback is appli ed to this second interferometer in an active demodulation scheme, all owing a linear tracking of the signal phase up to 7-pi radians.