To realize all-optical passive detection of CH₄ in narrow spaces and harsh environments, a compact cantilever-enhanced fiber-optic photoacoustic sensor (CEFPS) resistant to electromagnetic and ambient noise interference is proposed. Through theoretical analysis and finite element simulation, a miniaturized photoacoustic cell (PAC) with diffusion holes has been designed and fabricated. The diffusion holes are used for the circulation of the gas to be measured and attenuate the external noise coupled into the PAC. The concentration information of CH₄ is obtained by demodulating the vibration amplitude of the built-in cantilever generated by the photoacoustic pressure. The design of the built-in cantilever structure avoids the possibility of mechanical damage and reduces the interference of external noise in the detection of photoacoustic signals. The experimental results and the Allan-Werle deviation analysis of the CH₄ signal show that the minimum detection limit (MDL) is 0.32 ppm with an integration time of 60 s. The normalized noise equivalent absorption (NNEA) coefficient is calculated as 2.44 × 10⁻⁸ cm⁻¹ W/Hz^1/2. The developed CEFPS achieves performance comparable to conventional resonant photoacoustic spectroscopy CH₄ detectors, although the volume is two orders of magnitude lower.

_{为了在狭窄空间和恶劣环境中实现CH 4}的全光无源检测，提出了一种抗电磁和环境噪声干扰的紧凑型悬臂增强型光纤光声传感器（CEFPS）。通过理论分析和有限元模拟，设计并制作了具有扩散孔的微型光声电池（PAC）。扩散孔用于被测气体的循环，并衰减耦合到 PAC 中的外部噪声。_{CH 4}的浓度信息是通过对光声压力产生的内置悬臂的振动幅度进行解调得到的。内置悬臂结构的设计避免了机械损伤的可能性，减少了外界噪声对光声信号检测的干扰。实验结果和CH ₄信号的Allan-Werle偏差分析表明，最小检测限（MDL）为0.32 ppm，积分时间为60 s。归一化噪声等效吸收(NNEA)系数计算为2.44×10 ^-8 cm ^-1 W/Hz ^1/2。开发的 CEFPS 的性能可与传统的共振光声光谱 CH _4相媲美探测器，尽管体积要低两个数量级。