面向气体检测的VCSEL型激光器电流调制系统研制

Design of current modulation system of VCSEL laser for gas detection

对比TDLAS激光气体检测技术中所采用的核心光源器件,VCSEL激光器相较于传统DFB激光器具有阈值电流低,系统功耗小等优点。本文以LPC804作为主控制器,通过其内部DA产生数控锯齿波信号,同AD9834所产生的正弦波进行信号叠加,经电压转电流电路后对VCSEL型激光器进行驱动调制;并采用电流采集电路实现激光器过流、断路监测。经实验测试,本系统可在0~20 m A的电流范围内稳定工作,其控制精度达到0. 01 m A,可普遍适用于采用VCSEL型激光器的TDLAS气体检测系统的驱动调制应用场合。

Compared with the core light source devices used in TDLAS laser gas detection technology,VCSEL laser has the advantages of low threshold current and low system power consumption compared with traditional DFB laser.In this paper,LPC804 is used as the main controller to generate numerical control sawtooth signal through its internal DA,and superposition the signal with the sine wave generated by AD9834.Through the voltage to current circuit,the VCSEL laser is driven and modulated.The current acquisition circuit is used to monitor the laser overcurrent and circuit break.The experimental results show that the system can work stably within the range of 0~20 m A current,and its control precision reaches 0.01 m A.It can be widely used in driving modulation applications of TDLAS gas detection system with VCSEL laser.