The Design Of Driver On Switch-mode Constant Temperature Control System Of Semiconductor Laser Diode

EDFA(Er Doped Fiber Amplifier) and online RAMAN amplifier, made the capacity and distance of the information transferred in optical fiber develop farther. Semiconductor laser diode, as a core device of optical fiber communication, has the character of high efficiency, small size, low weight, high reliability, direct modulation and high-integrated ability with other semiconductor devices.Semiconductor laser have been applied to spectrum,communication,laser light and radar e.t field. In order to attain the high-effect and stable laser lamp-source, except design of stable antrum form, many influence factor(machine vibration,air harass,environment temperature)must be take into account. Thereinto, for the stable character of laser, precision temperature control of inner crystal component has important effect. At the same time, semiconductor laser diode is very sensitive to the temperature. The fluctuation of surrounding temperature not only leads to the fluctuation of supply current, but also makes threshold current, quantum efficiency, output wavelength and output light intensity of the laser diode change greatly. No matter which field semiconductor laser diode is applied to, it is always expected to work long and steadily. Especially in the benthic optical fiber communication system, semiconductor laser diode is required to work more than 25 years. However, actually used semiconductor laser diode cannot meet people's demand. Except of factor of the laser diode itself, many other factors result in the deterioration and unsteadiness of the device, such as the fluctuation of surrounding temperature, improper drive current, frequent impulse and heat dissipation. Therefore, the stable and constant control of semiconductor laser diode is rather important.The stable and constant control system of semiconductor laser diode includes constant current control, constant power control and constant temperature control. This paper is belonging to the design and research category of constant temperature control system. The constant temperature control system include liner mode and switch mode. Compare to liner mode, the switch mode have merits, such as efficiency high and consume small. The research content of this paper is driver part of switch-mode constant temperature controller.The main work of this paper is provide matting for the wholetemperature control system. Aimed to the driver problem of TEC,this paper designs a digital PWM power driver circuit based onsingle chip microcomputer. By using switch mode to drive TEC, thecore part of switch-mode constant temperature will maked up.Digital PWM power driver can provide bid-direction and sizeadjustable current, so it can control TEC to accomplish temperature control. At the some time, a new circuit was also put forward to prevent MOSFET H-bridge arms from cross-connection.Firstly, this paper studies the significance of semicon- ductor laser and analyses the product actuality of semiconductor laser constant temperature controller in country and abroad. This paper provied installation of semiconductor module and the according of component choused. Afterward, this paper demonstrates math module of digital PWM power driver, and analyses design theory of the every cell circuit, such as control part, voltage level-pulse width conversion part, driver end, computer communication, and gives up the data of experiment. Further, in order to apply the digital PWM power driver to semiconductor temperature controller, this paper also demonstrates in softwareway. Programs have been accomplish in temperature sensor resistor non-liner compensation, fuzzy-PID control arithmetic and RC digital filter. By using software to simulate, compensation andRC digital filter have good result. Fuzzy-PID control arithmeticneed more research in the further experiment.