An Acoustic Detector Based on Michelson Interferometer

Abstract

The invention discloses an acoustic wave detector based on Michelson interferometer, which comprises a narrowband light source, a photoelectric conversion unit, a data acquisition and analysis unit, and an acoustic wave detection sensing head; the input end of the acoustic wave detection sensing head is connected to the output end of the narrowband light source, The input end of the photoelectric conversion unit is connected to the output end of the acoustic wave detection sensor head; the input end of the data acquisition and analysis unit is connected to the output end of the optical end conversion unit; the acoustic signal is converted into an optical signal by the acoustic wave detection sensor head, and the optical signal is collected The optical signal is converted into an electrical signal through the photoelectric conversion unit, the electrical signal is collected by the data acquisition and analysis unit, and the frequency and sound pressure of the detected acoustic signal are obtained according to the electrical signal. The acoustic wave detector provided by the invention has the characteristics of good anti-electromagnetic interference ability and small volume, and especially greatly improves the sensitivity.

Description

technical field [0001] The invention belongs to the technical field of acoustic wave detection, and more specifically relates to an acoustic wave detector based on a Michelson interferometer. Background technique [0002] Acoustic wave detection can be used for health monitoring, disaster warning, geological exploration, etc. People have done a lot of research on acoustic wave detection instruments. The most commonly used acoustic wave detector is a capacitive microphone, which consists of a diaphragm, a plate, a front cavity, and a rear cavity. , where the diaphragm and the plate form a flat capacitor, called a single capacitor; the single capacitor microphone has the advantages of high sensitivity, small size, and strong output signal, but it has poor moisture resistance, low mechanical strength, and weak anti-electromagnetic interference. [0003] Acoustic measuring equipment based on fiber optic acoustic sensing technology has attracted widespread attention due to its sm...

AI Technical Summary

Problems solved by technology

Fabry-Perot interferometers are generally formed on the end faces of thin films and optical fibers. There are various types of films, such as silicon films, silver films, aluminum films, graphene films, etc., which have the characteristics of small size and good stability. The thin film manufacturing process is complicated, and the dynamic range of the detected sound pressure is limited; Michelson interferometers and Mach-Zehnder interferometers generally use one arm as a reference arm, and the other arm as a sensing arm, and the optical fiber sensing arm is pasted in the form of a coil On a thin film or an elastic cylinder, this acoustic sensor has high sensitivity, a large dynamic range for measuring sound pressure, and a simple manufacturing process, but the required sensing fiber is very long, which makes its polarization state, refractive index, etc. susceptible to interference, thereby affecting Measurement results, poor stability

Images