The Simulation Of 1550nm DFB-LD And Reserch For Uniform Gratings

With the development of the technology of fiber communications, the semiconductor lasers with thinner linewidth and higher side-mode suppression, are widely applied to high-speed and long distance communications. The distributed feedback laser(DFB-LD),as a dynamic and single longitudinal mode device, is turning into one of the best light source. As far as the distributed feedback laser is concerned,the design of the structure and material for the distributed feedback laser has important influence on the optical and electrical performance of the laser. The Photoelectricity Department in NO.13^th institute of China Electronic Technology group Corporation(CETC) got a large amount of research results for the quantum well laser and it has abundant practical experience.All of these permit us to continue our research about the technology of the distributed feedback laser.In the theory,a detailed nonlinear model has been developed of the performance of single-frequency laser structure,taking longitudinal-mode spatial hole burning into account.Comprehensive numerical simulation with the transmission matrix model(TMM) and the Newton function are used to simulate the 1550nm InGaAsP/InP distributed feedback laser. The results for the λ /4-shifed distributed feedback laser are compared with those for the distributed feedback laser with uniform gratings. The λ /4-shifed distributed feedback laser not only has high side-mode suppression ,but also may efficiently analysis the longitudinal-mode spatial hole burning and improve the design of the structure and material of the laser.Many experiments are performed.The etching process of the uniform grating for the semiconductor lasers by electron lithographic using several etching solution is studied.The technology has been optimized with which high-quality gratings are obtained. The HBr/HNO₃/H₂O solution is suitable to the semiconductor materials. The etching instance is analysized using scanning electron microscope(SEM), and the images of the semiconductor gratings are provided. By modifying the volume ratios (from 1:1:10 to 1:1:30) of the HB_r/HNO₃/H₂O solution,the good etching condition (at room temperature) and the optimum volume ratios (1:1:30) for etching InP are found. Using this kind of etching solution, the etching grating images can satisfy the requirement of the DFB semiconductor laser.