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基于偏振低相干干涉的高稳定性光纤麦克风传感系统

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提出一种基于偏振低相干干涉的高稳定性光纤麦克风传感系统.用于语音探测的麦克风由聚苯硫醚敏感膜片和光纤端面构成,与基于偏振低相干干涉技术的双折射晶体构成互相关传感系统.通过已知长度的双折射晶体提取干涉信号的直流分量,实现对外界环境等无关因素影响的补偿,从而达到高稳定性的目的.实验中对0.02~20.00 kHz的单频率声信号进行检测,该系统的信噪比均保持在50 dB以上;同时进行了不同性别的语音检测,并与参考麦克风进行对比;在传感器初始腔长漂移1.631 μm和系统输入功率衰减60%这两种情况下的输出语音,与系统未发生变化时输出语音的累积距离分别为0.29073和0.28154,证明该光纤麦克风具有良好的语音探测稳定性.该系统在灾难预警和矿难救援等领域中有较大的应用潜力.
Highly Stable Optical Fiber Microphone Sensing System Based on Polarization Low Coherence Interferometry
Objective Optical fiber microphones hold significant practical value in applications like mine safety monitoring and disaster relief,where they must maintain stable performance despite external environmental interference.Many researchers have proposed diverse design schemes for optical fiber microphones,significantly enhancing their sensitivity,minimum detectable sound pressure,and directional recognition capabilities.However,there is still a lack of comprehensive research on the accuracy of continuous speech detection and the robustness of optical fiber microphone systems.These performance metrics are particularly critical in fields such as mine safety and disaster response.In environments like mines or disaster zones,not only must microphones be highly sensitive to capture low frequency or faint sounds,but also maintain stable performance amidst temperature fluctuations and other environmental factors.Moreover,speech signals in these scenarios are often complex and varied,demanding microphone systems with advanced signal processing capabilities to accurately discern key speech information.Therefore,it is essential to conduct robustness research on optical fiber microphones.Methods In this paper,we propose a highly stable optical fiber microphone sensing system based on polarization low coherence interferometry.The microphone designed for voice detection comprises a polyphenylene sulfide sensitive diaphragm and an optical fiber end face,forming a cross-correlation sensing system with a birefringent crystal based on polarization low coherence interferometry.By extracting the DC component of the interference signal through a birefringent crystal of known length,we effectively compensate for external environmental factors,thereby achieving high stability.Results and Discussions To evaluate the frequency response characteristics of the experimental scheme,we test the optical fiber microphone across a frequency range of 0.02 to 20.00 kHz.The results,depicted in Fig.2,demonstrate that the optical fiber microphone system effectively detects sound signals within this range,maintaining a signal-to-noise ratio(SNR)consistently above 50 dB across all frequencies.To assess its capability in detecting speech signals,we test continuous distress voice signals from both female and male subjects,as shown in Fig.3.These findings highlight the system's accurate capture and reproduction of voice signals over a wide frequency spectrum.Long speech signals are also compared with those captured by a reference microphone.Furthermore,the system's performance under initial cavity length drift conditions is examined,with the outcomes presented in Fig.6.These experiments illustrate the optical fiber microphone's robust adaptability and stability in scenarios involving output light source attenuation and initial cavity length drift.Conclusions We introduce a highly stable optical fiber microphone sensing system based on polarization low coherence interferometry in this paper.The microphone includes a sensitive diaphragm made of polyphenylene sulfide material and an optical fiber end face,along with a cross-correlated sensing system formed by custom birefringent crystals on three paths at the rear end.By extracting the direct current component of the interference signal through a birefringent crystal of known length,the system effectively compensates for external environmental factors and other irrelevant interferences,thereby strengthening system stability.Experimental results demonstrate a signal-to-noise ratio of over 50 dB across the 0.02 to 20.00 kHz frequency range for this optical fiber microphone sensing system.Further detection and analysis of voice signals from different genders are conducted,followed by comparative analysis with a standard microphone.The system is also simulated under conditions of external environmental interference,where the initial cavity length of the sensor drifted by 1.631 pm and the system input power attenuated by 60%.Compared to unchanged conditions,the cumulative distances of the system's output voice signals are 0.29073 and 0.28154,respectively,showcasing the voice detection stability of this optical fiber microphone.Given these characteristics,the proposed optical fiber microphone sensing system holds significant application potential in disaster warning,rescue operations,and other scenarios requiring highly stable voice detection.It accurately captures crucial voice information in complex and dynamic environments,providing essential technical support for safety monitoring and emergency response in critical areas.

fiber opticsoptical fiber microphonelow coherence interferometryoptical fiber sensingvoice sensing

杨濠琨、王双、刘琨、李雪萍、李致远、江俊峰、刘铁根

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天津大学精密仪器与光电子工程学院,天津 300072

天津大学光电信息技术教育部重点实验室,天津 300072

天津市光纤传感工程中心,天津 300072

光纤光学 光纤麦克风 低相干干涉 光纤传感 语音传感

2024

光学学报
中国光学学会 中国科学院上海光学精密机械研究所

光学学报

CSTPCD北大核心
影响因子:1.931
ISSN:0253-2239
年,卷(期):2024.44(16)