A VIBRATION SENSOR, USING TELECOMMUNICATION GRADE MONOMODE FIBER, IMMUNE TO TEMPERATURE-VARIATIONS

A polarimetric fiber-optic vibration sensor immune to temperature vari ations is realized by forming coils using a standard single-mode fiber . The phase drift due to the linear birefringence changes induced by a modification of the environmental temperature is balanced by a feedba ck compression of a non vibrating coil. Experimental results show that without the feedback system the sensitivity to temperature is equal t o 2%/-degrees-C. The compensated device has a maximum 10% relative var iation of the output signal over a 30-55-degrees-C range. This method is easy to implement on polarimetric sensors over any range of tempera ture.