Research On High Power Single Longitudinal Mode Distributed Bragg Reflection Semiconductor Laser

The high-power narrow-linewidth semiconductor laser has a wide range of applications in spatial coherent optical communications,precision measurement,and pump sources for optical fibers and solid-state lasers.In this paper,a distributed Bragg reflector(DBR) semiconductor laser is used to achieve high-power and narrow-linewidth performance.The longitudinal mode is selected through the Bragg grating,and finally the single longitudinal mode laser spectrum characteristic is realized.In order to reduce the process complexity as much as possible while increasing the power and optimizing the spectral characteristics,this paper carried out detailed simulations on the epitaxial structure and grating structure of the semiconductor laser,obtained the influence of the grating parameters on the spectral characteristics,and found an optimal New structure.Finally,the feasibility of the device was verified through experiments.The specific research content of this article is as follows:(1)The finite element method is used to design the optimal symmetrical epitaxial structure and the asymmetrical epitaxial structure.On this basis,the finite element method and the transmission matrix method are used to measure the four parameters of the grating(grating The period,etch depth,etch width,grating logarithm)are simulated,and the influence of grating parameters on the peak reflectivity and half-height width of the grating is obtained.At the same time,the advantages and disadvantages of the two epitaxial structures are compared.In order to maximize the use of light,a 49-order grating was finally determined,with a grating period of 7681 nm,a slot width of 1500 nm,a slot depth of 1900 nm,and a grating number of 15 pairs.The grating reflectivity is 6%,and the half-maximum width is about 3 nm.(2)Prepare the semiconductor laser with the above structure through experiments.No secondary epitaxy or anti-reflection coating is required in the preparation process,and the preparation process is simplified compared with traditional DBR semiconductor lasers.With an injection current of 700 mA,the power reaches 112 mW,and the side mode suppression ratio reaches 38 dB.Achieved the expected technical indicators.