Research On Cavity Films And Light Emitting Window Technology Of Surface-emitting Distributed Feedback Semiconductor Laser

N-plane surface-emitting distribution feedback?SE-DFB?semiconductor lasers have attracted widespread international attention due to their excellent light-emitting characteristics and application potential.With the rapid development of grating fabrication technology,the output power of SE-DFB semiconductor lasers has been further improved.However,the output power and stability of SE-DFB semiconductor lasers are still unsatisfactory due to the limitation of the development of key fabrication process.Aiming at such problem,this paper mainly focuses on the fabrication process of cavity films and N-plane light emitting window for 976nm SE-DFB semiconductor laser.The main research contents and results are as follows:?1?For the light emitting window and front cavity surface of laser,a double-layer antireflection film composed of Ta₂O₅ and SiO₂ was designed.The antireflection film was prepared by electron beam evaporation with ion assisted deposition technology.Testing results indicate that the transmittance at 976 nm is about 99.87%,and the film has a wide transmission bandwidth.In addition,the effects of ion assisted deposition and high temperature assisted deposition on the properties of ZnSe passivation film in electron beam evaporation deposition process were also investigated,and the preparation conditions of ZnSe passivation film for laser were clarified.?2?For back cavity surface of the laser,the HfO₂/Ta₂O₅/SiO₂ high-reflection film was designed and optimized.In order to improve the laser damage resistance,the high-reflection film has three pairs of HfO₂/SiO₂ with higher damage threshold at the laser incident plane,and the electric field peak is located in the SiO₂ layer with higher damage threshold.The experimental results show that the reflectivity of high-reflectivity film prepared by electron beam evaporation with ion-assisted deposition is 99.69%at 976nm and 99.71%at 1064nm,respectively.And the damage threshold of the high-reflectivity film reaches 11.2J/cm².?3?In order to further improve the laser damage resistance of the high-reflection film on the back cavity surface of lasers,the thermal annealing process of designed HfO₂/Ta₂O₅/SiO₂ high-reflection film was studied.With the increase of annealing temperature,the transmittance spectrum of high-reflection film shifts to short wavelength,and the crystallinity of the film material is improved.After thermal annealing,the damage threshold of the films reached a maximum of 22.4J/cm² at 300?,nearly twice as much as that of the unannealed films.With the further increase of annealing temperature,the damage mechanism of the films changes from thermal stress damage to thermal explosion damage,which leads to the decrease of the damage threshold.?4?For the structural characteristics of the N-plane light emitting window of laser,the substrate thinning and polishing process is optimized,and the number of pits on the surface of the substrate after polishing is effectively reduced.The fabrication process of the N-plane electrode of laser is designed.In order to form regular light emitting windows on N-plane electrode,positive glue converted into negative glue process and Lift-off process are used.And double-side alignment lithography technology is used to overlap the light emitting window on the N-plane electrode vertically with the P-plane grating area.The SE-DFB semiconductor lasers with the N-plane light emitting window fabricated by the above process achieved a continuous output of 102mW at 1.8A current from the N-plane light emitting window.