研究了光频域反射技术(OFDR)中因激光线宽有限而造成的激光相位噪声对系统性能的影响。理论推导了相位噪声的分布函数,仿真分析和实验测试了激光相位噪声与激光相干长度、反射信号强度之间的内在关联性。研究结果表明,激光相位噪声是OFDR中的重要噪声来源,影响着系统的测试精度和可测距离,当测试距离接近相干长度、链路中存在强的反射信号时,激光相位噪声的影响将更加严重、影响范围也将增加。因此,在OFDR的设计和应用中必须对激光相位噪声问题予以高度关注和设计考虑。 The influence of laser phase noise on system performance due to the limited laser linewidth in optical frequency domain reflectometry (OFDR) was studied. The distribution function of phase noise is deduced theoretically. The internal correlation between laser phase noise and laser coherence length and reflected signal intensity is simulated and analyzed experimentally. The results show that the laser phase noise is an important source of noise in OFDR, which affects the system’s test accuracy and measurable distance. When the test distance is close to the coherence length and there is a strong reflected signal in the link, the laser phase noise will be more affected Serious, the scope of influence will also increase. Therefore, in the design and application of OFDR, the problem of laser phase noise must be highly concerned and designed.