Research On Optimization Of VCSEL Laser Simulation Model

In modern communication technology,fiber optic communication has been widely recognized by the industry for its advantages such as high speed,high capacity,and accurate transmission.The laser is one of the most core components in the optical fiber communication transmission system,which largely determines the quality and efficiency of the system's information transmission.As an important member of the laser family,the vertical cavity surface emitting laser(VCSEL)has low threshold,high efficiency,singlelongitudinal mode operation,and easy high-density large-scale integration.It is one of the most widely used lasers in the communications industry.Before VCSEL lasers are used in optical fiber communication transmission systems,engineers need to establish reliable mathematical models to accurately simulate their operating characteristics,so as to understand their operating characteristics under various conditions,and ensure the normal operation of optical fiber communication transmission systems.Based on investigating the static working characteristics and small signal response characteristics of VCSEL lasers at home and abroad,this paper uses the widely used mathematical and physical methods and models in the communications industry,which is combined with the optical power-working current curve,voltage-current curve,amplitudefrequency response curve measured at a specific temperature,to establish research on simulation of working characteristics of VCSEL laser.In terms of simulation of static operating characteristics,the L-I model based on empirical formulas is selected,and a variety of non-linear fitting methods are used to achieve the key parameter including(?,Ith0,Rrh,a0,a1,a2,a3,a4)in L-I model,which are consistent with the experimental measurement results.In addition,combined with the actual operating environment,a convection heat transfer term is introduced into the L-I model,and the existing L-I model is modified to obtain a more reasonable working model.In the study of small signal response characteristics,a bandwidth model based on the rate equation is selected,and multiple nonlinear fitting methods are used to extract key parameters including(?i,?,?n,k,G0,N0,?p,?)in the bandwidth model.In the meanwhile,the effect of parameters on the amplitude-frequency response curve is analyzed.In addition,the current bandwidth model based on the rate equation is a general small signal response model,which has no relationship with the structure of the laser.This paper draws on the simulation ideas of the amplitude-frequency characteristics of electronics to establish a new bandwidth model,which builds an equivalent circuit based on the actual physical structure of a VCSEL laser.The new model is used to simulate the small-signal response characteristics and the simulation results are compared with experiment to obtain an initially verification.In summary,this paper first simulates the static operating characteristics and small signal response characteristics of VCSEL lasers by using the classic L-I model and a bandwidth model based on the rate equation.Based on the experimentally measured data,the key parameters of the L-I model and the bandwidth model were extracted using the method of multiple nonlinear fitting.Secondly,based on the actual working environment of VCSEL laser,the existing L-I model is improved.Finally,an equivalent circuit model of the VCSEL laser is established,and its small-signal response characteristics are simulated,providing theoretical support for the simulation of the VCSEL laser.