基于多谐波混频和非线性曲线拟合的相位解调算法  

Phase Demodulation Algorithm Based on Multi-Harmonic Mixing and Nonlinear Curve Fitting

作　　者：黄怿[1] 赵宗领 蔡冰涛[2] 胡程勇 邓传鲁[1] 张琦[1] 陈伟[1] 张小贝[1] 王廷云[1] Huang Yi;Zhao Zongling;Cai Bingtao;Hu Chengyong;Deng Chuanlu;Zhang Qi;Chen Wei;Zhang Xiaobei;Wang Tingyun(Key Laboratory of Specialty Fiber Optics and Optical Access Networks,Joint International Research Laboratory of Specialty Fiber Optics and Advanced Communication,Shanghai University,Shanghai 200444,China;The 23rd Research Institute of China Electronics Technology Group Corporation,Shanghai 201900,China)

机构地区：[1]上海大学特种光纤与光接入网省部共建国家重点实验室培育基地,特种光纤与先进通信国际合作联合实验室,上海200444 [2]中国电子科技集团公司第二十三研究所,上海201900

出　　处：《光学学报》2024年第21期27-36,共10页Acta Optica Sinica

基　　金：国家自然科学基金(62022053,62027818,62205192,62275148);111计划(D20031);上海市自然科学基金(22ZR1423000,22ZR1424800,22010500100);江苏省产业前瞻与关键核心技术-重点项目(BE2022055-4);中国船舶航海保障技术实验室开放基金(2023010102)。

摘　　要：为了消除相位生成载波解调算法中相位调制深度漂移和载波相位延迟引起的非线性失真,提出一种基于多谐波混频和非线性曲线拟合的改进算法。该算法利用三对参考载波分量与干涉信号混频消去相位延迟项;然后,利用列文伯格-马夸尔特非线性曲线拟合算法获取的误差补偿方程,对调制深度漂移引起的非线性误差进行补偿;最后,采用符号恢复方法对解调信号的符号进行恢复。仿真和实验结果表明,改进方案的信纳比达到54.52 dB,总谐波失真低至-63.04 dB,解调系统的输入输出线性度高达99.99%。相比于传统算法,改进算法不受调制深度漂移和相位延迟的共同影响,具有更高的稳定性和更低的谐波失真。该研究为光纤传感器在实际应用中的信号处理方案提供了参考。Objective Interferometric fiber optic sensors are widely used in underwater target detection,oil and natural gas prospecting,and earthquake monitoring due to their high sensitivity,large dynamic range,immunity to electromagnetic interference,and ease of large-scale array implementation.The phase-generated carrier(PGC)demodulation technique is a crucial signal processing scheme for these systems,offering a simple optical structure,large dynamic range,high resolution,and good linearity.However,traditional PGC arctangent(Arctan)and PGC differential cross multiplication(DCM)algorithms are affected by light intensity disturbance(LID)phase modulation depth(C value)drift and carrier phase delay(θ),leading to nonlinear distortions in the demodulation results.Additionally,if theθis a singularity(kπ/4),the phase signal may not be recovered.Methods To simultaneously eliminate the effects of these factors,we propose an improved scheme with high stability and low harmonic distortion,which combines a multi-harmonic mixing technique,a nonlinear curve fitting algorithm,and a sign recovery method.First,we mix the in-phase and quadrature components of three pairs of reference carriers with the interference signal,followed by low-pass filtering to eliminate high-frequency carrier components.The signals without the carrier phase delay term are obtained by squaring and summing the filtered signals.The Levenberg-Marquardt(LM)nonlinear curve fitting algorithm is then applied to derive an error compensation equation that relates J_(3)(C)/J_(1)(C)to J_(2)(C)/J_(1)(C).This allows us to obtain J_(2)(C)/J_(1)(C)in real time,compensating for nonlinear errors caused by C value drift.As the multi-harmonic mixing involves square root operation,we use the sign of the filtered signal to recover the demodulated signal.For phase singularities(kπ/4),the filtered signal becomes noise,requiring an efficient sign recovery method.Our method identifies phase singularities,determines the phase delay range,and selects the appropriate sign recovery func

关 键 词：光纤光学 相位生成载波 相位调制深度 载波相位延迟 多谐波混频 非线性曲线拟合 符号恢复 

分 类 号：TP212[自动化与计算机技术—检测技术与自动化装置]