Study On The Thermal Characteristics And Process Improvement Of940nm Strained Quantum Well Lasers

Fiber laser as the important laser light source in optical communications sensingand processing areas，its working conditions require high power excitation lightsource，formed the number of carriers reverse distribution. Semiconductor lasers asthe only practical light source for fiber optic communications systems, its pumpingefficiency is limited by the ion-doped fiber work material that matches the absorptionband. Yb3+doped fiber in present is the mainstream as its strongest absorption peaknear976nm, however, due to the very sharp peaks, the wavelength shift of theabsorption change is large, so the wavelength and the bandwidth requirements arevery strict. Having an absorption peak near940nm will appear a high absorptionbandwidth, in the high doping concentration, it does not likely to occur concentrationquenching phenomenon, so that the940nm semiconductor laser becomes a bestchoice for the pumping source of Yb3+doped fiber.Double quantum well laser have higher output power and electro-opticalconversion efficiency than a single quantum well laser, it also has a lower thresholdcurrent and better thermal characteristics than multiple quantum well laser; InGaAsquantum wells as compared AIGaAs/GaAs quantum wells will better able towithstand stress in active region, and the carrier recombination lower heat production,it will help to improve the characteristics of the device. Combining the above twopoints, this article design the940nm wavelength InGaAs prepared double quantumwell semiconductor laser, pulsed12.1W output power obtained prior to coating,electro-optical conversion efficiency of up to42.5%conversion efficiency increasedto48.4%after coating. The main research work is shown as follows:First, we did a detailed study on the principles of high power semiconductor laserlasing. And then, we simulated thermal distribution of a laser which designed with940nm InGaAs double quantum well semiconductor laser structure.Second, based on the study of the thermal characteristics of940nmsemiconductor laser, exploring the actual temperature characteristics of the device byexperiment.Third, based on the traditional high-power semiconductor lasers produce process,conducting research to improve and perfect the specific process of940nm laser, Including the effects of solvents on the wet etch rate and depth of etching, the etchingdepth of the strip influence the performance of the device, the substrate and the effectof thinning the bonding stress is reduced growth of electrode material and thethickness of the device reliability.Fourth, successfully prepared940nm high power semiconductor laser in theoptimal design and the optimal process conditions, also, test andevaluate the performance of the device, as the result, it can reach the leading domesticlevel.Fifth，further explores the testing process itself affect the device, propose theconcept of testing the thermal relaxation time, contribute to a more accurateassessment of device performance.