Dual-Enhancement Fiber-Optic Photoacoustic Sensor for Trace Gas Detection

A miniature fiber-optic photoacoustic sensor featuring dual signal enhancement is developed for trace gas detection. The design synergistically combines optical path length amplification via a Herriott cell with acoustic signal amplification via a silicon cantilever resonator. The resultant weak photoacoustic wave is detected by a fiber-optic Fabry-Perot(F-P) acoustic sensor. This configuration achieves high-performance trace gas sensing within a compact, all-optical architecture. System evaluation based on the Allan-Werle deviation confirms a minimum detection limit of 4.4 ppb at an average time of 100 s. The all-optical detection scheme inherently eliminates electromagnetic interference.