High-frequency strain measurements using a laser diode with a fiber Bragg grating external reflector

摘要

A technique for detection of high-frequency strain using an AR-coated laser diode with a fiber Bragg grating to form a short (approximately 1 cm) external cavity is reported. The laser system becomes a single mode, narrow-linewidth (30 MHz) source under the influence of the grating's feedback. An interferometric detection technique was used to demodulate the strain signals generated by a piezoelectric transducer into a steel block. The sensing system was able to detect frequency components up to 140 kHz.