Use of SDR Receivers for Recording Signals from Fiber-Optic Interferometric Sensors with RF Modulation of a Laser Diode

A new method for constructing a measurement system for interrogating fiber-optic interferometric sensors has been experimentally demonstrated. This method is based on a software-defined radio receiver (SDR, Analog Devices PlutoSDR plus). The object of investigation is a Mach−Zehnder interferometer subjected to acoustical action from a low-power dynamic head and a step motor. A key feature of the proposed approach is to use a single SDR device in two functions: as a generator of an RF modulating signal for a laser source and as a receiver/demodulator for the photodetector signal of the interferometer. The fundamental applicability of the method for recording acoustic vibrations by receiving and processing the RF signal has been experimentally shown.