一种提高光纤水听器解调系统噪声传递系数稳定性的多相相位生成载波解调算法  

A Multi-Phase Phase-Generated Carrier Demodulation Algorithm for Stability Improvement of Noise Transfer Coefficient for Fiber Optic Hydrophone

作　　者：侯庆凯 姚琼[1] 陈虎 熊水东[1] Hou Qingkai;Yao Qiong;Chen Hu;Xiong Shuidong(Institue of Deep-Sea Science and Technology,College of Meteorology and Oceanology,National University of Defense Technology,Changsha 410073,Hunan,China)

机构地区：[1]国防科技大学气象海洋学院深海科学技术研究所,湖南长沙410073

出　　处：《光学学报》2024年第2期135-143,共9页Acta Optica Sinica

摘　　要：相位生成载波(PGC)调制解调是干涉型光纤水听器常用的解调方法。首先,分析并建立了PGC解调系统的噪声传递模型,研究了光源强度噪声对PGC解调输出噪声的影响机理,分析了调制深度和工作点两个参数对PGC解调噪声稳定性的影响。然后,提出了一种基于3×3耦合器的多相PGC解调方案,即在传统PGC解调架构中引入3×3耦合器进行多相检测,利用3×3耦合器的相移特性对三路干涉信号进行融合处理。在不同的调制深度条件下,该方案可以降低水听器工作点变化所引起的光源强度噪声传递系数波动范围。实验结果显示,在常用的调制深度范围(1.7~3.4)内,工作点变化导致的噪声传递系数波动峰谷值小于0.5 dB,噪声稳定性相比传统PGC解调系统显著提升。Objective Interferometric fiber optic hydrophone is a relatively mature solution in the current fiber optic hydrophone system and features high sensitivity,large dynamic range,strong anti-interference ability,and easy array formation.Meanwhile,it is suitable for underwater targets and is widely employed in fields such as detection and underwater energy exploration.In recent years,the application scenarios of fiber optic hydrophones have gradually developed into complex scenarios such as far-reaching seawater acoustic detection and mobile platform deployment.These scenarios pose more challenges to the signal detection performance and noise stability of hydrophones.Phase-generated carrier(PGC)demodulation is a commonly adopted signal detection method for interferometric fiber optic hydrophones.Since the operating point and carrier modulation depth are greatly affected by external environmental changes,the PGC demodulation system has unstable output phase signals.In particular,the system's self-noise stability fluctuates greatly with environmental changes.This problem has become an important factor limiting the performance of fiber optic hydrophone systems.Methods Centering on the noise stability of interferometric fiber optic hydrophones based on PGC demodulation,we build a noise transfer model of the interferometric fiber optic hydrophone based on PGC demodulation and focus on analyzing changes in the two parameters of the carrier modulation depth and operating point.Meanwhile,the mechanism of influence on the stability of PGC demodulation noise is studied.A new multi-phase PGC demodulation scheme is proposed,where a 3×3 coupler is introduced into the traditional PGC demodulation architecture for multi-phase detection,and the three interference signals are fused by phase shift characteristics of the coupler.The multi-phase PGC demodulation algorithm performs PGC demodulation on the outputs of three 3×3 couplers respectively,and then averages the demodulation results of the three channels.Since the measured phase

关 键 词：干涉型光纤水听器 相位生成载波解调 噪声稳定性 3×3解调 

分 类 号：O436[机械工程—光学工程]