调频连续波激光调制方法研究

调频连续波(FMCW)激光调制电路是FMCW激光探测系统的重要组成部分。对FMCW激光调制方法进行研究,设计并实现由线性调频信号产生电路和半导体激光器驱动电路组成的激光调制电路,并给出相应的实验结果。其中线性调频信号产生电路采用基于直接数字频率合成技术的集成芯片AD9958进行设计,产生10~110 MHz的锯齿波线性调频信号;半导体激光器驱动电路采用直接电流调制方式,利用线性调频信号对激光载波的强度进行调制,激励激光器出光。测试结果表明:调频连续波激光调制电路能够满足调制频偏100 MHz、调频周期100 s的设计要求。

Method of frequency modulated continuous wave laser modulation

Frequency modulated continuous wave(FMCW)laser modulation circuit is an important part of the FMCW laser detection system. In this paper, the method of FMCW laser modulation was studied and a laser modulation circuit composed of a linear frequency modulation signal producing circuit and a semiconductor laser driver circuit was designed and implemented. Experimental result is given. The linear frequency modulation signal producing circuit was designed using the direct digital synthesis chip AD9958 and produced a 10-110 MHz sawtooth linear frequency modulation signal. The semiconductor laser driver circuit modulates the laser intensity with the linear frequency modulation signal through direct current modulation. Test results show that the laser modulation circuit can meet the design requirements:frequency deviation of 100 MHz, frequency modulation period of 100 s.