Modeling And Simulation Of Equivalent Circuit Of Double Quantum Well Semiconductor Laser Based On PSpice

Semiconductor lasers are important light sources in high-speed optical communication systems,and have received considerable attention due to their broad application prospects and enormous development potential.It is of great significance to study tunable double quantum well semiconductor lasers with low threshold current,high optical output power,short delay response time,and good gain switching characteristics.The process of semiconductor lasers is relatively complex,and testing their performance after fabrication requires significant time and cost.Optoelectronic integrated circuit computer aided design(OEIC CAD)technology is an important part of electronic design automation(EDA)in optoelectronic devices.By constructing equivalent circuit models to simulate the output characteristics of lasers,it can save costs and shorten the development cycle,which has an important guiding role for the design and manufacturing of semiconductor lasers.Based on the SPICE simulation tool and the rate equation of a double quantum well semiconductor laser,this paper introduces various circuit and device parameters,constructs an equivalent circuit model that can be used for simulation,and simulates its output characteristics.The main contents of the study are as follows:1.Starting from the rate equation of a single mode semiconductor laser,combining the nonlinear effect of gain,the carrier ABC recombination model,and the carrier transport phenomenon in a double quantum well,the rate equations of a double quantum well semiconductor laser are given.The rate equations are transformed into an intrinsic equivalent circuit model of a double quantum well semiconductor laser.After introducing various parasitic parameters,a complete equivalent circuit model of a double quantum well laser is formed.The results show that for symmetric double quantum well lasers,the threshold current can be reduced by reducing the transparent carrier concentration and ABC recombination coefficient,and increasing the differential gain coefficient and gain saturation coefficient;For asymmetric double quantum well lasers,by reducing the transparent carrier concentration in QW2 and increasing the differential gain coefficient and gain saturation coefficient in QW2,the threshold current of QW1 in the asymmetric double quantum well increases,while the threshold current of QW2 decreases.2.Based on the PSpice circuit simulation program,the equivalent circuit of a double quantum well laser is modeled.The relationship between output power and input current(P-I characteristics),time domain characteristics,and other output characteristics of a double quantum well laser in symmetric and asymmetric double wells were simulated.The effects of gain parameters,external injection current conditions,and parasitic circuit parameters on the output characteristics of the laser were investigated.The results show that for symmetric double quantum well lasers,optical pulses with high output power and small delay time can be obtained by increasing the DC bias current and electrical pulse amplitude,reducing the transparent carrier concentration and AC recombination coefficient,increasing the differential gain coefficient and gain saturation coefficient,and appropriately reducing the B coefficient and gain compression factor.For asymmetric double quantum well lasers,by reducing the transparent carrier concentration and gain compression factor in QW2,and increasing the differential gain coefficient and gain saturation coefficient in QW2,the optical output power of QW2 increases,while the output power of QW1 decreases.By reducing the AC coefficient in QW2,both QW1 and QW2 have higher optical output.3.By modulating the carrier transport time parameters and parasitic parameters in the equivalent circuit model of a double quantum well laser,the effects of carrier tunneling and transmission processes between double quantum wells and parasitic parameters on the laser pulse output characteristics were studied.The results show that by reducing the transmission time and increasing the tunneling time,the threshold value of QW2 in symmetric double quantum well lasers is smaller and has higher optical pulse peaks,while the threshold current of QW1 is larger and the optical pulse peaks are reduced.By increasing the metal wire capacitance and inductance in the parasitic circuit and reducing the value of the lumped capacitance,optical pulses with narrow pulse width and high peak value can be obtained.