VERDET CONSTANT LIMITED TEMPERATURE RESPONSE OF A FIBEROPTIC CURRENT SENSOR

A novel all-fiber, magnetooptic current transformer is reported, Chang es of the optical system response to current with temperature have bee n measured to be linear with a slope of 6.9 x 10(-5)/degrees C with an error bar of less than 0.2% over the temperature range of -40 to +80 degrees C. This temperature dependence can be entirely attributed to t he change in the Verdet constant of the glass. This is, to our knowled ge, the first report of a birefringence free fiber-optic current senso r with Verdet constant limited performance, The sensor's response to c urrent is linear to within 0.3% from less than one amp up to 110 amps, the limit of our measurement capability.