Design And Research Of High-precision Laser Driver Based On ADuC842

Semiconductor lasers play an irreplaceable role in the fields of military, medical, communications and so on, because of its monochromatic, well coherent, good collimation, high energy, low energy consumption, high efficiency. However, it's extremely sensitive to the operating current and temperature, the fluctuant current not only lead to the noise of the laser, but also causes a change in the wavelength of light. Heat generated by working also increases its threshold current, reducing its using life. In addition, some interruption such as surge and electrostatic will breakdown PN junction. To ensure that the laser can work stably and reliably, developing a small size, high stability, no inrush and continuously adjustable current, temperature-controlled laser driver has a relatively great practical significance.This paper analyzes the working principle, the characteristics and damage mechanism of the semiconductor laser. Based on this, I develop the objectives of this paper, and determine the system design. According to this plan, I design a semiconductor laser drive system with constant current drive and temperature control. In drive system, according to the target value of the key, the microcontroller outputs DAC voltage drive the laser by a voltage- current conversion of the constant current source, we use the PID algorithm to adjust the current output; in temperature control system, via controlling the driver chip to make a stable temperature; in addition I designed a variety of protection circuits.Finally, the system performance is tested and analyzed. I simulate the PID circuits, finding that the circuit meets the basic needs of the thermostat module. I have done a lot of experiments to test on precision of the current and long-term stability of current and temperature, finding that the system is expected to meet the target with high accuracy and stability. Then choosing DFB laser for the actual verification system, the output spectrum fluctuates little with stable light. In conclusion, this system meets the design goals fundamentally with good performance, it could satisfy the basic functionality of the laser driver.