Design of long-distance multichannel system based on passive optical fiber audio transmission system.

• Based on EFPI sensor, PB-AOF and wavelength division multiplexing technology, the system realizes one-way four-channel passive audio parallel transmission. • Achieve 20 km long distance optical fiber audio communication. • No difference between the EFPI sensors used by each channel. • Be used in scenarios with special requirements, such as security monitoring and mines. To meet sound transmission requirements in complex work environments, this paper constructs a passive audio pickup sensor based on an extrinsic Fabry-Perot interferometer (EFPI) and develops a one-way four-channel passive audio parallel transmission system based on a passive bidirectional audio over fiber(PB-AOF) transmission system and wavelength division multiplexing technology. The system realizes optical fiber audio transmission over a distance of 20 km. The experimental results show that the signal-to-noise ratio (SNR) is greater than 64 dB, and the highest sensitivity of the four channels in the proposed system is 1.06 V/Pa. Thus, the proposed long-distance terminal passive audio communication network is ideally suited for applications in certain fields. [ABSTRACT FROM AUTHOR]