Research On Driver Power Of Semiconductor Laser Array Of Key Technology

The paper studies the two significant electronical control technologies of semiconductor laser array which can work well. As the current modulation principle of semiconductor laser array’s drive, the output power of the semiconductor laser is linear to the current input of the semiconductor array, so the stablization of current input is the basic requirements of the semiconductor laser array. Because of the large output power and difficult process, the semiconductor laser array is expansive and can be damaged easily, so the semiconductor laser array driver power must have guarantee its safety including no-surge, overvoltage and overcurrent etc. The semiconductor laser array’s power is closed with its temperature. The threshold current increases with the temperature, so the property curve of the whole laser moves up and down with the changes of the temperature. When the environment temperature changes, laser output power will change greatly, so another important technology is its temperature control. LD current source works in two ways:one is constant current mode, another is constant light power mode. About the constant current mode, the loop is controlled by electronic feedback, which giving the efficient control of the drive current and voltage and getting the lowest current deviation and the best output stability. In the constant light power mode, it is difficult to control the temperature because of the current changes. So surveillance photoelectric diode-or other-external detector must connect with feedback circuit to realize the drive current control.With the property of the drive power, constant current charging circuit is adopted in this paper. The technology of PWM(pulse width modulaton) is used to control the output current of the swith power supply. The current PWM is more stable and credible than voltage PWM. Semiconductor laser array temperature control circuit adopts H bridge drive chip and MCU composition. Employing the temperature sensor to feedback laser tube core temperature, then the MCU process to control the TEC circuit. According to the direction of the current, the TEC circuit cool or heat the semiconductor laser array to accurately control the temperature of the semiconductor laser array.