| In recent years,Internet technology has developed rapidly,the modernization has become more advanced,and the society has entered an information age centered on big data.In order to meet the increasing demand of data transmission,high transmission speed,and low transmission power consumption,optical interconnection technology using multimode fiber as the transmission link came into being,and quickly occupied the market with an irreversible trend,vertical cavity surface emission Laser as a light source of optical fiber transmission link has also received more and more attention.The vertical cavity surface emitting laser is a semiconductor laser whose light output direction is perpendicular to the surface of the chip.It has small size,low power consumption,low threshold current,high temperature stability,high speed modulation,nearly circular output spot,easy fiber coupling,and easy integration.advantage.With the demand for high bandwidth and low power consumption in optical interconnection and optical communication,high-performance vertical cavity surface emitting lasers have become the mainstream light source in this field.Therefore,the performance of vertical cavity surface emitting lasers has been optimized to increase their modulation speed and modulation bandwidth,and reduce their power consumption.Consumption is of great significance.This thesis takes high-speed vertical cavity surface emitting lasers as the research object,and experimentally studies the key processes of high-speed vertical cavity surface emitting lasers in the manufacturing process.At the same time as studying the key manufacturing processes,a theoretical simulation of optimizing the performance of vertical cavity surface emitting lasers is also conducted.The specific research contents of this paper are as follows:First this article introduces the research background and significance of the vertical cavity surface emitting laser,expounds the research progress of the vertical cavity surface emitting laser in terms of modulation speed,high temperature characteristics,energy efficiency,and summarizes the optimization of the vertical cavity surface emitting laser based on these work progress.Methods,and summarize the application of vertical cavity surface emitting lasers.Second introduce the basic structure and basic theory of the vertical cavity surface emitting laser.Introduce the internal response and external response of the vertical cavity surface emitting laser in detail.We analyze the factors affecting the vertical cavity surface emitting laser,and the characteristics of the vertical cavity surface emitting laser,such as the distributed Bragg reflector,threshold gain,light limiting factor,threshold current density,longitudinal model and PAM4 modulation mode,etc.,Meanwhile we introduce the basic principles and characteristics of PN junction.Third introduced the preparation process of vertical cavity surface emitting laser photolithography,dry etching,thin film growth,BCB planarization process.The characteristics of BCB and its process steps are introduced in detail.The flattening of non-photosensitive BCB and photosensitive BCB is analyzed through experiments to finally determine the process parameters.The process flow and process parameters of the vertical cavity surface emitting laser are mainly introduced,and the possible situations and precautions of each experimental process are briefly summarized.Finally,the first time to make a large-scale process,the experimental results were not satisfactory,and the experience of the failed process was summarized.Forth compared with other semiconductor lasers,the vertical cavity surface emitting laser has a small volume,which makes the heat dissipation of the device a problem.Although the conversion efficiency of the vertical cavity surface emitting laser is relatively high,there is still a lot of energy consumed in the form of thermal energy.As a result,the temperature around the active area in the laser is too high,and the temperature in the active area will directly affect the performance and service life of the laser.Therefore,thermal analysis of the laser to improve the performance of the laser is of great significance.We take the vertical cavity surface emitting laser with a wavelength of 980 nm as the research object,and use the finite element analysis method to study their influence on the temperature of the active region from the four aspects of oxide aperture,oxide layer thickness,driving current and the material of the underlying Bragg reflector layer.The simulation results show that the larger theoxidation aperture of the laser,the lower the temperature of the active region,and the oxidation aperture is within a certain range,the laser has better modulation characteristics;changing the thickness of the oxidation limiting layer,the temperature of the active region does not change much,which indicates that the oxide layer does not Obvious thermal resistance characteristics;change the driving current of the laser,the temperature of the active region changes significantly,as the driving current increases,the temperature of the active region is higher;the effect of the underlying Bragg reflector of two materials on the temperature of the active region is compared The simulation results show that the underlying Bragg reflector made of binary system material has higher thermal conductivity than the underlying Bragg reflector layer made of ternary alloy material.The temperture is higher in the active region,thedifferential gain of the device is lower,and the performance of laser is worse.These thermal field simulation results have important guiding significance in optimizing the laser design.Fifth Filling the tunnel junction in the vertical cavity surface emitting laser not only reduces the resistance of the laser,but also limits the current laterally.The current-voltage,impurity doping concentration,electron tunneling probability,tunneling current and other characteristics of the tunnel junction are briefly introduced,and the tunnel junction doping concentration on the tunneling probability,tunneling current and tunnel junction depletion layer width are deeply studied.The greater the tunnel junction doping concentration,the greater the tunnel junction’s probability of tunneling electrons,the greater the tunneling current,and the smaller the depletion layer width.Moreover,the doping concentration of the N region has a greater influence on the tunnel junction than that of the P region. |
