Hybrid Opto-Mechanical Current Sensor Based on a Mach-Zehnder Fiber Interferometer

In this paper, a new optical sensor based on a Mach-Zehnder interferometer, constructed with single mode optical fibers operating at 1.55 μm has been proposed and studied. The current sensing is obtained by mechanical perturbation applied to one of the single mode fiber, which constitutes the interferometer. This disturbance leads to an optical interference detected in the output of the interferometer and it is proportional to the magnitude of the current in the driver, measured with a reference sensor. The sensor has been tested with ac (60 Hz) up to 110 A. The obtained calibration curve presents a sensitivity between 0.8 and 1.54 mV/A. With a variation on the experimental arrangement, the sensor can be used in the monitoring of low and high amplitude currents. This new sensor can be efficiently used for monitoring the alternating electrical current in both small and large electric power suppliers and consumers.