Time-resolution enhanced multi-path OTD measurement using an adaptive filter based incoherent OFDR  

作　　者：王立晗 任凌云 王祥传 潘时龙 Lihan Wang;Lingyun Ren;Xiangchuan Wang;Shilong Pan(National Key Laboratory of Microwave Photonics,Nanjing University of Aeronautics and Astronautics,Nanjing 210016,China)

机构地区：[1]National Key Laboratory of Microwave Photonics,Nanjing University of Aeronautics and Astronautics,Nanjing 210016,China

出　　处：《Chinese Optics Letters》2024年第1期153-158,共6页中国光学快报（英文版）

基　　金：supported by the National Natural Science Foundation of China(Nos.62075095 and 62271249);the Key Research and Development Program of Jiangsu Province(No.BE2020030)。

摘　　要：High accuracy and time resolution optical transfer delay(OTD)measurement is highly desired in many multi-path applications,such as optical true-time-delay-based array systems and distributed optical sensors.However,the time resolution is usually limited by the frequency range of the probe signal in frequency-multiplexed OTD measurement techniques.Here,we proposed a time-resolution enhanced OTD measurement method based on incoherent optical frequency domain reflectometry(I-OFDR),where an adaptive filter is designed to suppress the spectral leakage from other paths to break the resolution limitation.A weighted least square(WLS)cost function is first established,and then an iteration approach is used to minimize the cost function.Finally,the appropriate filter parameter is obtained according to the convergence results.In a proof-of-concept experiment,the time-domain response of two optical links with a length difference of 900 ps is successfully estimated by applying a probe signal with a bandwidth of 400 MHz.The time resolution is improved by 2.78times compared to the theoretical resolution limit of the inverse discrete Fourier transform(iDFT)algorithm.In addition,the OTD measurement error is below±0.8 ps.The proposed algorithm provides a novel way to improve the measurement resolution without applying a probe signal with a large bandwidth,avoiding measurement errors induced by the dispersion effect.

关 键 词：optical transfer delay measurement time resolution enhancement incoherent OFDR adaptive filtering 

分 类 号：TN713[电子电信—电路与系统] O43[机械工程—光学工程]