Investigation On Heat Dissipation Characteristics And Heat Sink Structure Of 25G Transmission Laser Diode In Coaxial Package

Semiconductor lasers(LD),as a core device in the field of optoelectronics and with advantages of small size,high photoelectric conversion efficiency,direct modulation,is widely used in areas of optical communication,automatic control,military,medical and biological etc.However,LD is also a temperature-sensitive component,with the increase of output power,the waste heat generated by the laser is also increasing,which leads to negative effects such as temperature increase in the active region,reduction in electro-optical conversion efficiency,and red shift of the lasing wavelength.Therefore,it is particularly important to improve the heat dissipation problem and study the thermal characteristics of LD.Based on the research progress at home and abroad,according to the theory of thermal characteristics of LD,the influence of temperature rise on threshold current,output power,slope efficiency,wavelength and service life of lasers were analyzed.Additionally,several basic packaging forms of lasers were introduced.The main work of this paper included:(1)Based on the heat conduction theory,a heat source model was established to analyze the temperature distribution parallel to the cavity length and perpendicular to the cavity length.Simultaneously,the influence of different temperature environments on the laser chip was analyzed.The results showed:when temperature increased,the heat dissipation effect becomed worse.(2)According to the principle formula of semiconductor refrigeration,the maximum temperature difference and refrigeration coefficient under the optimal current point were deduced.Combined with the simulation model,the refrigeration characteristics of two different semiconductor materials were analyzed.At the same ambient temperature,compare with Ph Te,the maximum temperature control of Bi₂Te₃can be increased by 5.03K,and the slope coefficient is increased by about 1 K/W;for the same semiconductor material,with the increase of the temperature,the optimal current point did not change significantly,the overall thermal resistance would increase linearly,and the figure of merit coefficient would gradually decrease,and the cooling coefficient would continue to increase.(3)The deficiencies of typical heat sink structure were analyzed,and a new type of flat heat sink structure model was proposed.The differences in heat dissipation effects of primary heat sinks and secondary heat sinks of different materials were compared.Furthermore,the optimal length of the primary heat sink was determined.The temperature of the chip after steady state in high and low temperature environment was simulated.By temperature control,the temperature drift was 1.25?in high temperature enviroment and 0.5?in low temperature enviroment,compared with the high temperature drift of 11.76?and the low temperature drift of 7.66?when TEC was not added,the heat dissipation effect was significantly improved.(4)The actual samples of the two structures were produced,and the measured data were compared and analyzed.Under the high temperature environment,the average wavelength drift of the optimized new structure can be controlled at 0.1523 nm,the threshold current was reduced by about 0.28 m A,and the stability of the output wavelength was improved by about 24%.