Thermal Analysis And Temperature Control Of TO-CAN Packaged LD

The advantages of LD, such as small size, light weight, reliable, high efficiency, and so on, make LD become the core of optoelectronic technology. But when the semiconductor laser at work, there are various causes of loss which make a part of electrical energy will convert to heat energy, that cause the LD’s temperature to rise. And the rise of LD’s temperature have an effect on LD’s threshold current, output power and the service life, so in the study of the semiconductor laser, the temperature control become an important research direction.Thermoelectric Cooler (TEC) is the device which uses semiconductor’s thermoelectric effect to control temperature. It has many advantages which make it gain quick development in many fields. First of all, it’s structure is simple, weight is light and size is small. Second, it cooling fast and convenient to control. Third, it don’t use refrigerating fluid, won’t cause any pollution. Last one, it is reversible, we can control the heating or cooling by change the work current direction. When the great progress was made in the miniaturization of semiconductor refrigerating unit, it’s size can achieve millimeter order of magnitude, that makes it one of the best choices for LD to control temperature.We do the thermal simulation in two cases:TEC work and TEC don’t work. When TEC do not work, we analyze steady state and transient state of the TO-CAN model under the condition of different outer circumstance temperature. To observe the temperature distribution by the temperature field cloud picture, and analyze the trend of variation in temperature with the change in time.When TEC works, we simulate the two cases of power constant and change. First, under the same external environment temperature, we set TEC power as a constant value, and test the temperature changes of TO_CAN model, compare with the situation TEC do not work. Second, in order to control temperature convenient, we design method to dynamic control the power of TEC. It can adjust the TEC power according to the detected temperature so adjust the internal temperature to reach the steady state as soon as possible. Finally, we design an improved dynamic method to control TEC power dynamically. We call it "multi-stage control method", which can detect the further refinement temperature, taking different measures in different temperature range. Compared with the second method, the last method has a faster convergence speed and better convergence.