Miniature laser vibrometer system with multifunction integrated optic circuit

A miniature laser vibrometer system (LVS) that uses a proton-exchanged LiNbO/sub 3/ multifunctional integrated optic circuit for signal processing is discussed. The system uses a pigtailed 0.83- mu m laser diode as the source and common-path interferometry to provide a phase-insensitive fiber-optic probe for monitoring moving or vibrating parts. The LVS provides a 55-dB signal-to-noise ratio for 3-kHz bandwidth, even when monitoring parts with relatively low (1%) reflectivity. The optical components and all electronics are housed in an 11.5-cm*10.5-cm*4.2-cm package which operates from a +or-15-V, 300-mA supply.<>