ELECTRONICALLY SCANNED WHITE-LIGHT INTERFEROMETRIC STRAIN SENSOR EMPLOYING HIGHLY BIREFRINGENT FIBERS

An electronically scanned strain sensor employing highly birefringent fiber as a sensing element and using a low-coherent light source is de scribed. The sensor is composed of two sections of exactly equal lengt h of HB fiber spliced at 90-degrees. This structure compensates the sp atial coherence mismatch which enables application of a Wollaston pris m alone without expensive bulk delay line as a receiving interferomete r, and assures good temperature stability of the sensor. Absolute meas urements of strain within the range up to 4000 mustrain with apparent temperature cross-sensitivity less than 1.3 mustrain/degrees-C are pos sible with this sensor.