Available Technology

DISPLACEMENT SENSOR WITH EMBEDDED COHERENT ELECTROMAGNETIC RADIATION INTERFEROMETER FOR MICRO SCALE PROXIMITY MEASUREMENTS

A displacement sensor is constructed with a laser diode interferometer in which the sinusoidal phase-modulation (SPM) is produced by modulating the injection current of the laser diode between two laser beams reflected by an object surface and an inner surface of the optical fiber respectively. The interference signal with the SPM frequency of 1.5 MHz is sampled at different five points during a halt period of the SPM frequency.The sampled values are processed with electric curcuits to obtain quadrature signals of the phase of the interference signal from which the displacement is finally obtained. 
Inventors: 
Nicholas Dagalakis, Yong-sik Kim
Patent Number: 
8,437,006
Internal Laboratory Ref #: 
10-012
Lab Representatives
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