Study On The Near-field Nonlinearity Deformation Of Semiconductor Laser Diode Array And The Reduction Methods

According to many characteristics of semiconductor laser diode,such as high power,high efficiency,high reliability,small size and light weight,semiconductor lasers have been widely used in medical cosmetology,industrial processing and scientific research applications.At the same time,with the improvement of chip production technology(the improvement of power/ efficiency and reliability),the development of efficient cooling materials and the development of electronic packaging technology and equipment,semiconductor laser has gradually become one of the most reliable and widely used light sources.However,the near field nonlinear SMILE effect is one of the most important factors affecting the direct application of semiconductor lasers by decreasing the beam quality.The near-field nonlinear effect of semiconductor lasers is mainly caused by the thermal induced packaging stress during the packaging process,resulting in that each of emitter is not in a line.As a result,the quality of laser beam is poor after collimation,which affects many applications of laser diode.Most of the previous studies mainly focused on the testing characterization methods of semiconductor lasers,the reduction methods and the effect of SMILE effect on the beam quality,etc.,but there were few studies on the mechanism of SMILE effect and most of reduction measurements have other side effect,like low reliability.Therefore,this paper focuses on the mechanism of near-filed nonlinear effect of semiconductor lasers and reduction measurements.The following research work has been carried out:1.Study on the mechanism of near-field nonlinear effect of semiconductor lasers array.SMILE effect has big different for different bonding technology.Based on the SMT(surface mounting technology)process,the mechanism of SMILE effect will be studied by mechanics models.2.Model the theory of SMILE effect of semiconductor laser array.Based on the Bi-metal/Tri-metal and Qua-metal mechanics models,optimizing the theory models to meet the requirement of different structure packaging of semiconductor laser diode array,analysis the strain and stress of different structure packaging.3.Test the packaging induced thermal stress and SMILE effect of semiconductor laser diode array.In order to research the packaging induced strain and stress of laser diode array,an easy method to measure the thermal induced stress is proposed based on lase wavelength shifting.The mechanical contact scanning probe and optical imaging method are used to test the SMILE effect and value.4.Study on the factors affecting the SMILE effect of laser diode array.According to the Bi-metal/Tri-metal and Qua-metal mechanics models of semiconductor laser diode array,packaging materials(Young's Modulus and CTE),packaging structure(the thickness of heat sink and submount)and packaging technology(bonding temperature)have been studied to affect the SMILE effect of laser diode array.5.Research on the reduction measures of SMILE effect.Based on the affecting factors of packaging materials/structure and technology,three reduction measures have been proposed.Based on the packaging materials,bending against method has been proposed to reduce the SMILE effect;based on the packaging structure,balancing thermal stress method has been proposed;based on the packaging technology,low temperature bonding has been proposed.6.Develop a laser diode array with high power,high reliably and low SMILE value device.Based on the balancing thermal stress method,the output power of high-power single bar under continuous operation CW is 250 W,with an efficiency of over 65%,a SMILE value less than 0.5 micron,and a high reliability life of over 20,000 hours are realized.