Design of semiconductor laser driver circuit and analysis of loop noise -suppression

In order to prevent the fluctuation of driving current from affecting the laser excitation wavelength and luminous power, a sinusoidal modulation driving circuit of semiconductor laser with strong anti-interference ability was designed. The driving circuit takes the deep negative feedback architecture as the core, and sends control instructions by serial port. Through STM32 controller, the magnitude of dc signal in the setting voltage as well as the frequency and amplitude of sinusoidal signal were adjusted. First-order manual analysis of the whole loop was carried out, and a noise suppression network with automatically adjustable parameters was introduced by Tina-TI simulation.Experimental results show that the current driving circuit of the laser can suppress the loop noise of more than 10 times the target frequency by more than 20 dB.The maximum deviation between the output value of the frequency and the set value is 0.001 Hz, and the control linearity is 0.999 9. The short-term stability of the 2 hour driving current under dc bias is better than 0.005 6%, and the long-term stability is up to 0.011% at 63 hours. The control linearity of the laser power is 0.999 4, and the standard error is 0.092 87.