采用数模混合双闭环方法的DFB激光器驱动电源

由于驱动电流波动会影响分布式反馈式（DFB）激光器激射波长及发光功率，采用数模混合双闭环技术，以TMS320LF28335为核心控制器，设计并研制了一种高稳定性DFB激光器驱动电源。在硬件电路设计方面，该激光器驱动电源采用运算放大器深度负反馈原理，提高了系统的稳定性（优于410-5）。软件设计中，引入Ziegler-Nichols PID算法，消除了实际驱动电流值与理论值之间的微小差异（小于0.5%）。同时，该驱动电源具备防上电/断电冲击保护电路、延时软启动电路和过流保护电路等保护电路。利用该驱动电源，对中心波长为1742 nm的DFB激光器做了驱动测试。实验表明，在长时间（220 h）稳定性测试中，驱动电流稳定度优于410-5（RMS），满足DFB激光器对驱动电流的要求，具有很强的实用价值。

DFB laser driving power using hybrid digita-analog closed loop

As the driving current fluctuation can affect distributed feedback (DFB) laser's emitting wavelength and optical power, a high stable DFB lasers driver was designed and developed by using hybrid digita-analog closed loop method, which was based on TMS320LF28335 core controller. In terms of hardware design, the proposed laser driver utilized operational amplifier deep feedback theory to increase the stability of the whole system (better than 410-5). In software design, Ziegle-Nichols PID algorithm was introduced to eliminate the micro deviation between the real driving current and the theory current value (less than 0.5%). Meanwhile, the driver possessed surge protection circuit when power was on/off, time delay soft start circuit and over current protection circuit, et al. Using the aforementioned driver, a driving test was performed on a DFB laser with a center wavelength of 1 742 nm. Experiments show that the stability of driving current is better than 410-5 (RMS) during long term (220 h) stability performance test, which meets the requirement of DFB laser and has good practical significance.