A RECIPROCAL-COMPENSATED FIBEROPTIC ELECTRIC-CURRENT SENSOR

A novel reciprocal-compensated structure is proposed and demonstrated for intensity-modulated intrinsic fiber-optic current sensors. Both th e component losses and birefringence influences can be partly compensa ted using this configuration, and the sensor is sensitive only to nonr eciprocal Faraday rotation. The dependence of the signal on circular b irefringence drift can be reduced by a factor better than 10 for low b irefringence fibers. The property of total reciprocity reduce the sens itivity of the current sensor to temperature changes and vibrations. T he experimental results agree well with the theoretical predictions fo r the sensor, fabricated using a coil of low birefringence single-mode fiber.