High Power Semiconductor Laser thermal solution
Semiconductor lasers were first studied from abroad. The earliest technology originated from the United States and Japan, and was mainly used in the military. With the iterative development of technology, it began to be applied to the civilian market and applied in industries such as optoelectronics and communications. With the development of my country's national defense industry and optoelectronic manufacturing industry, the industry has begun to increase the demand for high-power lasers, and people have also begun to conduct research on high-power semiconductor laser devices. During the research, it was discovered that the light quality of traditional semiconductor lasers could no longer meet the needs of people. In order to increase the output power of semiconductor lasers, people began to continuously improve and analyze. During the research, it was found that half of the electric energy of the semiconductor laser is converted into heat energy when it is in use. If the semiconductor laser itself does not dissipate heat well, it will directly affect the life and use of the semiconductor laser. Therefore, the heat dissipation problem is urgently needed to be solved by researchers now. One of the problems.
At present, the main cooling methods of lasers are divided into traditional cooling methods and new cooling methods. Traditional cooling methods include: air cooling, semiconductor refrigeration, natural convection cooling, etc., and new cooling methods include: flip chip cooling and microchannel cooling.
Natural convection heat sink cooling method is to use some materials with high thermal conductivity to take away the heat generated, and then dissipate the heat through natural convection.During the research, the scientific and technical personnel also found that the fins can also help dissipate heat, and can maximize the heat transfer rate in the heat dissipation system when dissipating heat. When the temperature is the same, the fin pitch will decrease as the fin height increases. When using the substrate to place the heat sink vertically, the height needs to be appropriately increased, and the heat dissipation effect is improved by increasing the height. Such a heat dissipation method will reduce a lot of costs when used. In actual work, copper or aluminum nitride is often used as a heat sink, but the heat sink method cannot fully meet the heat dissipation needs of high-power semiconductor lasers.
Large channel liquid cooling method . If you want to lower the temperature of the heat sink, you need to build a channel in the heat sink. If you want to achieve the cooling effect, you need to add a certain water source to this channel, so as not to delay the work of the laser. In response to this, researchers found during their research that the heat dissipation effect of the spoiler structure is better than that of the traditional cavity structure, but the pressure increase in the channel will also occur. Research has found that although large channels are widely used, because of the continuous increase in laser output power, large channels of water cooling can no longer meet the thermal requirements of high-power semiconductor lasers.
Spray cooling is to spray the cooling liquid to the heat transfer surface by means of atomization with the help of pressure to achieve the purpose of cooling. The main characteristics of spray cooling are large heat transfer coefficient and low coolant flow. Researchers have found that when using water as the medium and using solid cone nozzles for experiments, the microstructured surface can increase the heat exchange effect. During the study, it was found that the cooling performance of spray cooling is related to the spray flow rate. In addition, the researchers also discovered a spray phase change cooler. During the experiment, the nozzle height in the spray cooling device and the heat dissipation effect are also very closely related.
The problem of chip temperature rise has gradually become the primary factor hindering the normal operation of semiconductor lasers. New heat dissipation methods are constantly deepening research. To solve the heat dissipation of high-power semiconductor lasers, we must firmly grasp the thermodynamics discipline, materials science, and fully cooperate with the manufacturing industry.
