介绍了腔长调制线性调频信号体制引起激光相干性降低的实验研究。对这种影响的机制提出一种理论分析，认为腔长调制可能使激光器谐振腔端镜产生随机振动，从而影响激光的相干长度 The experimental study on the reduction of laser coherence caused by the cavity length modulated chirp signal system is introduced. A theoretical analysis is put forward on the mechanism of this kind of influence. It is believed that the modulation of the cavity length may cause random vibration of the endoscope of the laser resonator and thus affect the coherent length of the laser