Passive Bidirectional Audio-Over-Fiber System Integrating Sensing, Power Supply, and Communication

Although numerous efforts have been dedicated toward developing optical communication system with high performances, challenges still remain in achieving communication in special scenarios, such as mines where flammable and explosive gases are present. Aiming at the problem, a passive bidirectional audio-over-fiber (PB-AOF) system that integrates sensing, power supply, and communication has been proposed, enabling passive bidirectional audio transmission across a 10-km single-mode fiber (SMF). In the uplink system, distributed acoustic sensing (DAS) technology is used to achieve distributed audio sensing across the entire span of the optical fiber. In the downlink system, power-over-fiber (PWoF) technology is used, using a self-designed InGaAs/InP photovoltaic power converter (PPC), to achieve simultaneous power and signal transmission to the downlink terminal. The system not only achieves distributed audio transmission with frequency response range up to 5 kHz and signal-to-noise ratio (SNR) of more than 50 dB over a distance of 10 km in the uplink but also provides an SNR of more than 50 dB of the audio signal after 10 km of fiber-optic transmission in the downlink. The downlink has a power transfer efficiency of up to 24%.