A Fabry–Perot Interferometer-Based Fiber Optic Dynamic Displacement Sensor With an Analog in-Phase/Quadrature Generator

Research on the Frequency Response and Dynamic Range of the Quadrature Fiber Optic Fabry–Perot Cavity Microphone Based on the Differential Cross Multiplication Demodulation Algorithm

“…Using the frequency at which the output signal attenuation reached 3 dB as the upper limit of the frequency response range, the simulation yielded the upper limit of the frequency response range ( f c ) of the demodulated signal; and the ratio (C) of the upper limit of the frequency response range to the signal sampling rate was calculated, as shown in Table 3. Table 1 shows that under the condition that the demodulated signal intensity is not attenuated by more than 3 dB, the upper limit of the amplitude of the phase change of the interference spectrum caused by the sound signal, the upper limit of the frequency response range, and the system signal sampling rate are related by Equation (9).…”

“…Various FOMs have been developed, including intensity-type, wavelength-type, and interference-type [6][7][8]. In recent years, interference-type FOMs have become a research hotspot, especially FOMs based on Fabry-Perot (F-P) interferometers [9][10][11], which are of great interest due to their high sensitivity, simple structure, and easy fabrication. However, the dynamic range of the fiber optic F-P cavity microphone is largely limited by the intensity demodulation method based on a linear region of the interference spectrum [12][13][14].…”

Non-contact sub-nanometer displacement sensing based on optical digital coherent detection using frequency-domain filters

“…Although some progress has been made in published research, challenges persist. These include the need to establish feedback connections between the transmitting and receiving ends for the lock-in demodulation of interference signals [17]. The inherent phase difference in couplers in multi-port optical interference systems may lead to a low signal-to-noise ratio (SNR) [18].…”

Fast interrogation of dynamic low‐finesse Fabry‐Perot interferometers: A review

“…Up to now, low‐finesse F‐P sensors play an increasingly important role in dynamic measurement. Related applications can be divided into three types: (a) rapid temperature, pressure, humidity, and other physical quantities measurement, such as rapid temperature sensing for ocean turbulence monitoring, 1 fast humidity measurement for breathing monitoring, 2 fast pressure measurement for pulse wave monitoring; 3 (b) acoustic vibration sensing, such as fiber optic accelerometer, 4 fiber vibrometer, 5 photoacoustic spectroscopy, 6 photoacoustic imaging, 7–9 and partial discharge positioning, 10–12 and so on; (c) dynamic displacement or distance measurements for precision machining 13–15 . Generally, signal demodulation techniques largely determine the performance of the entire sensing system.…”