Packaging Stress Study On Semiconductor Lasers

With the development of semiconductor lasers,people are increasingly demanding semiconductor laser device performance and reliability.High-power semiconductor laser chip fabrication process is relatively complex and the production cost is high.The packaging stress due to bad parameters of the packaging process seriously restricts the device yield and reliability,and limits the large-scale production of HPLD(High Power Laser Diode).This article explains the causes of semiconductor laser package stress,and the energy band theory is used to derive and explain the effect of package stress on the lasing wavelength and polarization characteristics of semiconductor laser bars.Using ANSYSY software to simulate the size and distribution of package stress under different package parameters.In order to quickly and effectively detect the packaging stress of semiconductor lasers,an experimental method was designed to reveal the package stress distribution by detecting the polarization degree,threshold current,and laser wavelength of each unit of the laser bar.Experiments show that the low degree of polarization of the individual light emitting units of the bar and the higher threshold current are due to the larger package stress.By calculation,the package stress is 141.92 MPa,and the maximum polarization equivalent stress is 26.73 MPa.Experiments show that the degree of polarization of the device below the threshold reflects the distribution trend of the packaging induced stress,and the degree of polarization of the device can be measured by using the following threshold current.It can provide a quicker and more efficient method for selecting the heat sink and the solder material and the improvement of the welding process parameters.