In order to investigate the factors affecting the acoustic performance of the extrinsic Fabry–Perot interferometer (EFPI) fiber-optic acoustic pressure sensor and to effectively improve its detection capability, this paper enhances the sensor’s detection sensitivity by adding more sensitized rings to its acoustic pressure-sensitive film. Furthermore, a novel real-time coupled acoustic test method is proposed to simultaneously monitor the changes in the spectral and acoustic metrics of the sensor to characterize its overall performance. Finally, an EFPI-type fiber-optic acoustic pressure sensor was developed based on the Micro-Optical Electro-Mechanical System (MOEMS). The acoustic tests indicate that the optimized fiber-optic acoustic pressure sensor has a sensitivity as high as 2253.2 mV/Pa, and the acoustic overload point (AOP) and signal-to-noise ratios (SNRs) can reach 108.85 dB SPL and 79.22 dB, respectively. These results show that the sensor produced through performance characterization experiments and subsequent optimization has a very high acoustic performance index, which provides a scientific theoretical basis for improving the overall performance of the sensor and will have broad application prospects in the field of acoustic detection.

In environments like coal mines and oil wells, electrical equipment carries the risk of disasters such as underground fires and methane gas explosions. However, communication equipment is essential for work. Our team has developed a long-range (approximately 25 km) audio transmission system that operates without the need for terminal power sources, thereby eliminating the risk of electrical sparks. This system leverages the reliability of optical fiber and employs a 1550 nm laser for analog audio transmission. After traveling through 25 km of optical fiber, the signal is converted back into electrical energy using a custom-designed Laser Power Converter (LPC). The optical fiber’s carrying capacity imposes limits on the light signal intensity, which, in turn, affects the signal transmission distance. To enable long-distance transmission, we have carefully chosen the optical wavelength with minimal loss. We observed that different LPC structures operating within the same wavelength band have an impact on the audio quality at the terminal. By comparing their characteristics, we have identified the key factors influencing audio output. The optimal LPC allows audio transmission over 25 km, with an output exceeding 12 mVrms.

The signal-to-noise ratio (SNR) is a crucial parameter for assessing audio transmission quality and fiber optic acoustic sensors. This study presents a model for predicting the SNR of a fiber optic F-P acoustic sensing system using the Fabry–Perot (F-P) cavity length modulation principle, considering noise and line loss in the optical path. To validate the model, we constructed an F-P acoustic sensor system and measured the SNR in a semi-anechoic room. Additionally, we used MATLAB to simulate the SNR model and compared the results with experimental data. The model accurately predicted the SNR of the fiber optic F-P acoustic sensor system. Our results offer valuable guidance and theoretical support for optimizing system performance.

Current–voltage (I–V) curve measurement is an essential performance characterization technique for laser power converters (LPCs). Choosing an appropriate scan time can effectively avoid problems in the test process that lead to inaccurate data. We analyzed the I–V curve error of a GaAs LPC in relation to scan time by building a test system for LPCs. A method for determining the optimal scan time, defined as a time period containing the upper limit and lower limit, is presented. The effects of the temperature of a measured GaAs LPC were investigated through comparative tests, and the upper limit of the scanning time was determined. The hysteresis of the equivalent capacitance in GaAs LPCs was analyzed. The upward limit of the scanning time was determined by establishing the relationship between the hysteresis of the I–V curve and the scanning time. It was concluded that the optimal scanning time of GaAs LPCs in the same structure ranges from 10 ms to 1 s.