Stability improvement of DFB laser driving power using digital position PID algorithm

To ensure the stability of output power of Distributed Feedback(DFB) lasers, which was effected by the emitting current, a high stable DFB lasers driver using positional digital PID algorithm was proposed. In terms of hardware design, the aforementioned driver was composed of controller model, constant current model and protection circuit model. The analog Proportion-Integral(PI) deep negative feedback loop was utilized to enhance the stability and precision of driving current effectively. In consider of software design, a positional digital PID algorithm was introduced to eliminate the micro deviation between the real driving current and the theory current value. Using the aforementioned driver, a driving test was performed on a DFB laser with a center wavelength at 1 563.01 nm. Experimental results show that long term(more than 100 h) stability is better than 410-5 and the center wavelength without any shift, which could provide DFBs with excellent performance security for the application of infrared gas detection.