Power Modulation-Based Optical Sensor for High-Sensitivity Vibration Measurements

An intensity modulation-based curved waveguide sensor is developed in this paper for vibration measurements. Measurement of vibration is an important aspect in aerospace and automotive structures. The sensor is created using a single-mode optical fiber, where coupling between the fundamental and cladding modes at certain curvatures results in intensity peaks that enables the development of a high-sensitivity sensor. The sensor is calibrated at known frequencies and the functionality of the sensor is tested by measuring the complex vibration response of composite material beams. The results are validated by direct measurements through an alternate technique. Results confirm the possibility of using the fiber-optic sensor for vibration measurements. The present validation studies are conducted up to the frequency of 1 kHz; however, further testing may show a wider operating frequency range for the sensor.