Laser-Induced Acoustic Air-Water Trans-Medium Communication Based on PWM

Abstract

Laser-induced acoustic communication has emerged as a critical technology for facilitating air-water trans-medium nodeless communication, garnering increasing attention in research and application. At higher repetition frequencies, traditional modulation and demodulation techniques based on single-pulse recognition face challenges due to exacerbated interference among pulses, significantly disrupting code element determination and leading to high error rates that impede effective communication. To address this issue, a novel laser-induced acoustic communication method employing pulse width modulation (PWM) was proposed. Experiments utilized an Nd:YAG pulsed laser with a maximum repetition frequency of 500 Hz, and the number of laser pulses was adjusted to generate PWM signals of varying widths, with code element recognition achieved at the receiving end based on pulse width. The experiment results show that the PWM-based communication method effectively minimizes decoding errors due to inter-pulse interference, achieving commendable performance at the highest repetition frequency of 400 Hz with an error rate of just 8%. This improvement significantly enhances the reliability and effectiveness of laser-induced acoustic communication at high repetition frequencies.

Keywords

• trans-medium communication
• laser-induced acoustics
• nodeless
• pwm modulation