基于内调制DFB激光器的高空间分辨率 TGD-OFDR  

High Spatial Resolution TGD-OFDR Based on Internally Modulated DFB Laser

作　　者：戴建平 邱锦波 刘宏睿 罗一民 刘庆文 Dai Jianping;Qiu Jinbo;Liu Hongrui;Luo Yimin;Liu Qingwen(China Coal Technology and Engineering Group Shanghai Co.Ltd.,Shanghai 200030,China;State Key Lab of Advanced Optical Communication Systems and Networks,Shanghai Jiao Tong University,Shanghai200240,China)

机构地区：[1]中煤科工集团上海有限公司,上海200030 [2]上海交通大学区域光纤通信网与新型光通信系统国家重点实验室,上海200240

出　　处：《光学学报》2023年第7期253-260,共8页Acta Optica Sinica

基　　金：中煤科工集团上海有限公司科技开发项目(017819)。

摘　　要：提出了一种利用内调制频率调谐实现高空间分辨率的时间门控数字光频域反射仪(TGD-OFDR)方案,采用电流调谐的分布式反馈(DFB)二极管激光器作为探测光源提供较大的激光频率调谐范围的信号,利用马赫-曾德尔干涉仪(MZI)分析该DFB激光器的电流-频率响应特性后,由任意波形发生器产生的带有预失真的锯齿波信号驱动该DFB激光器,进而补偿激光器扫频时的非线性,同时采用一台波长可调节的稳频激光器的出射光充当本地稳频参考光。实验测试在74 km的光纤链路上实现了10 cm的空间分辨率,动态范围为23.3 dB。Objective An optical reflectometer is a powerful optical instrument,and it is widely adopted in distributed fiber optic sensors for loss location and temperature and stress measurement.Usually,optical reflectometers include optical time domain reflectometers(OTDRs)and optical frequency domain reflectometers(OFDRs).OFDR uses a sweeping laser as the light source.Compared with OTDR,it has higher spatial resolution and larger dynamic range.However,when the detection length is longer than the coherence length of the light source,the phase noise will degrade the system performance greatly.Meanwhile,a high spatial resolution requires a wide range of sweeps of the probe light.Because of the high cost of narrow linewidth lasers and modulators,OFDR is difficult to be commercialized at present.Therefore,most OFDR studies focus on phase noise and sweep ranges.There are already many ways to suppress OFDR phase noise,such as narrow linewidth lasers and coding and phase compensation algorithms.Time-gated digital optical frequency domain reflectometry(TGD-OFDR)is also a method proposed in recent years to suppress phase noise and improve detection length.The frequency sweep method of OFDR is generally divided into external modulation and internal modulation.External modulation has better sweep performance and is easier to be controlled,but the sweep range is limited.The internal modulation has a large sweep range,but it has problems such as nonlinearity of the sweep frequency and linewidth broadening,and compensation or correction is often required through other means.Therefore,designing low-cost,long-range,and high-resolution TGD-OFDR systems is the main work in this paper.Methods The TGD-OFDR system has the characteristics of a simple structure,which can effectively overcome phase noise and achieve long-distance detection.By taking the advantages of low cost,easy integration,and high sweep range of distributed feedback(DFB)lasers,an internally modulated DFB laser is selected as the swept frequency light source,and a TGD-OFDR sy

关 键 词：传感器 光纤测量 时间门控数字光频域反射仪 分布式反馈激光器 预失真 

分 类 号：TP212[自动化与计算机技术—检测技术与自动化装置]