摘要
本文提出了一种应用于光纤延时系统中实现光纤延时精密测量的新方法,用以提高光纤延时测量的精度和准确性.该方法以1064 nm激光调制信号作为光源,通过测量回波信号的幅值和相位信息得到被测通道的频率响应,采用快速傅里叶逆变换得到被测目标的延时信息,实现光纤延时测量.本文通过理论分析和延时测量实验对频域反射法与传统的时域测量方法进行对比,使用频域反射法在调制频率范围10—200 MHz,采样频率间隔0.5 MHz的实验条件下,实现了3.3 ps延时测量分辨率,并证明了该方法具有比时域方法更高的测量精度,测量结果的准确性更好.
Optical fiber time delay system has been widely used in optical-controlled phased array antenna,radar distributed network,interferometric optical fiber hydrophone and high-speed photoelectric chip.These applications require high-accuracy and high-stability time delay generated by the system.Time delay measurement directly determines the precision and resolution of the system.Therefore,high-precision time delay measurement method is of great significance in developing the optical fiber delay system.In this paper,progress and problems of optical fiber time delay measurements are discussed.A new method of precisely measuring the time delay in optical fiber is proposed.We use the frequency domain reflectometry(FDR)to avoid the discrepancy between measuring range and measuring precision,which exists in both time-of-flight(TOF)method and phase discrimination approach.An intensity modulated 1064 nm laser signal is used as a light source.The modulation frequency is tuned from 10 MHz to 200 MHz in steps of 0.5 MHz.The spectrum of echo signal is obtained by measuring the amplitudes and phases of echo signals at different frequency points.The delay information is obtained via the inverse fast Fourier transform(IFFT).The precision of delay measurement in our method is determined by step size of frequency variation,and a higher-precision measurement is realized by using interpolation zero algorithm.Since our method is not to modulate the optical frequency,but to control the frequency of the modulation signal loaded on the electro-optic modulator,it is easy to achieve the high-precision and high-linearity frequency modulation.In this paper,theoretical analysis and time delay measurement are used to compare the FDR method with conventional TOF measurement method.The accurate measurement of 33–200 ps is realized,and measurement error is lower than 7 ps.We also design an incremental measurement experiment to study the resolution of the FDR method,which achieves a delay resolution of 3.3 ps.The influence of temperature jitter is analyzed to prove the reliability of experimental results.It proves that the FDR method has a higher measuring accuracy than the TOF method.The time delay measurement precision can be further improved by expanding the modulation bandwidth.Our method is to be applied to an optical fiber delay system to improve the precision and resolution of system delay.
作者
赵天择
杨苏辉
李坤
高彦泽
王欣
张金英
李卓
赵一鸣
刘宇哲
Zhao Tian-Ze;Yang Su-Hui;Li Kun;Gao Yan-Ze;Wang Xin;Zhang Jin-Ying;Li Zhuo;Zhao Yi-Ming;Liu Yu-Zhe(School of Optics and Photonics,Beijing Institute of Technology,Beijing 100081,China;R&D Center,Beijing Research Institute of Telemetry,Beijing 100076,China)
出处
《物理学报》
SCIE
EI
CAS
CSCD
北大核心
2021年第8期134-140,共7页
Acta Physica Sinica
基金
国家自然科学基金(批准号:61835001,61875011)资助的课题。
关键词
频域反射法
光纤延时
频谱分析
精密测量
frequency domain reflectometry
optical delay
spectral analysis
precision measurement
