//VerilogA for ring,neffreso,veriloga //Xuanqi Chen, Zhifei Wang, Yi-Shing Chang, Jiang Xu, Jun Feng, Peng Yang, Zhehui Wang, Luan H. K. Duong, ”Modeling and Analysis of Optical Modulators Based on Free-Carrier Plasma Dispersion Effect,” IEEE Transactions on Computer-Aided Design of Integrated Circuits and Systems (TCAD), vol. 39, no. 5, pp. 977-990, May 2020. `include "constants.vams" `include "disciplines.vams" `define MAX_TABLE_SIZE 300000 `define MAX_X_NUM 1000 //500*500=250000 module neffreso(Ipow,Iphase,Ilam,Opow,Ophase,Olam,Vbias,Gnd); //Parameters parameter real r = 10u from (0:inf); parameter real phaseshift_ratio = 0.8407 from (0:1); parameter real nref_coupler = 3.02 from (0:inf); parameter real kappa_coupler = 2.15e6 from (0:inf); parameter real l_coupler = 0.1u from (0:inf); parameter real alpha_phaseshift_ref = 80 from (0:inf); parameter real alpha_absorp = 1 from (0:inf); parameter real alpha_wd = 1 from (0:inf); parameter real rib_width = 0.4u from (0:inf); parameter real pn_offset = 0 from [0:inf); parameter real ni = 1e16 from (0:inf); parameter real N_A = 5e23 from (0:inf); parameter real N_D = 1e24 from (0:inf); parameter real Lp = 2u from (0:inf); parameter real Ln = 1u from (0:inf); parameter real epsr_Si = 11.7; parameter real Is = 1e-14 from (0:inf); parameter real IBV = 1000u from (0:inf); parameter real BV = 40 from (0:inf); parameter real V0 = 1 from [0:inf); parameter real Cj0 = 1.5p from [0:inf); parameter real tau = 0.5n from (0:inf); parameter real Rs = 55 from (0:inf); parameter real emi = 1 from (0:inf); parameter real Vt = 0.0259 from (0:inf); parameter string neff_ps_filename = "../../../data/EIM/outputPN1.54-1.56-500.txt"; parameter string neff_wg_filename = "../../../data/EIM/output-wg1.54-1.56-500.txt"; input Ipow,Iphase,Ilam,Vbias; output Opow,Ophase,Olam; inout Gnd; electrical Ipow,Iphase,Ilam,Opow,Ophase,Olam,Vbias,Nint,Gnd; branch (Gnd,Nint) Iint; branch (Nint,Gnd) CCj,CCd,Idd,RRs; //internal variables real beta_cp; real k_cp_r,k_cp_i; real t_cp_r,t_cp_i; real beta_wg; real k_wg_r,k_wg_i; real beta_ps; real k_ps_r,k_ps_i; real c1r,c1i,c2r,c2i,cr,ci; real er,ei; real p_mr_r,p_mr_i; real E_in_R,E_in_I,E_out_R,E_out_I; real alpha_phaseshift; real W,Wdp,Wdn; real eps,phi_bi,phi; real N_avr; real gd,Id,Cj,Cd; real pn00,np00; real lam; real neff_waveguide,neff_phaseshift_ref,neff_phaseshift; //1550nm real sigma_ne=-8.8E-22; real sigma_nh=-8.5E-18; real sigma_ae=8.5E-18; real sigma_ah=6.0E-18; real xlength;//=0.6u; integer xnum=`MAX_X_NUM+1; integer xnum2=2*`MAX_X_NUM+1; real x[0:`MAX_X_NUM]; real np[0:`MAX_X_NUM]; real pp[0:`MAX_X_NUM]; real pn[0:`MAX_X_NUM]; real nn[0:`MAX_X_NUM]; real xx[0:2*`MAX_X_NUM+1]; real n[0:2*`MAX_X_NUM+1]; real p[0:2*`MAX_X_NUM+1]; integer wi,wf; real dalpha_e[0:2*`MAX_X_NUM+1]; real dalpha_h[0:2*`MAX_X_NUM+1]; real dalpha[0:2*`MAX_X_NUM+1]; real sum_dalpha,dalpha_avr; integer ps_file, wg_file; real width_start, width_end, width_step; integer width_num; real lam_start, lam_end, lam_step; integer lam_num; integer lam_near, width_near; real tmp; real lam_old=0; real width_old=0; real neff_table_ps[0:`MAX_TABLE_SIZE] = {0}; real neff_lamtable_ps[0:`MAX_TABLE_SIZE] = {0}; real neff_widthtable_ps[0:`MAX_TABLE_SIZE] = {0}; real neff_table_wg[0:`MAX_TABLE_SIZE] = {0}; real neff_lamtable_wg[0:`MAX_TABLE_SIZE] = {0}; integer read_table_ps=1; integer read_table_wg=1; integer i, j; analog initial begin pn00=pow(ni,2)/N_D; np00=pow(ni,2)/N_A; eps=epsr_Si*`P_EPS0; phi_bi=`P_K*$temperature/`P_Q*ln(N_A*N_D/pow(ni,2)); N_avr=N_A*N_D/(N_A+N_D); end analog begin lam=V(Ilam); gd=(-Is*(exp(5)-1)+IBV)/(-5*emi*Vt + BV); Id=Is*(limexp(V(Nint)/(emi*Vt))-1)+V(Nint)*gd; if (V(Nint) >= V0) Cj=0; else Cj=Cj0/sqrt(1-V(Nint)/V0); //Cd=Id*tau/(emi*Vt); Cd=Is*(exp(V(Nint)/(emi*Vt))-1)*tau/(emi*Vt); I(Iint) <+ V(Vbias)/Rs; I(CCj) <+ Cj*ddt(V(CCj)); I(CCd) <+ Cd*ddt(V(CCd)); I(Idd) <+ Id; V(RRs) <+ I(RRs)*Rs; E_in_R=sqrt(V(Ipow))*cos(V(Iphase)/360.0*2*`M_PI); E_in_I=sqrt(V(Ipow))*sin(V(Iphase)/360.0*2*`M_PI); beta_cp = 2.0*`M_PI*nref_coupler/lam; //k_cp = 1j*sin(kappa_coupler*l_coupler) * limexp(1j*l_coupler*beta_cp) k_cp_r=-sin(kappa_coupler*l_coupler) * sin(l_coupler*beta_cp); k_cp_i=sin(kappa_coupler*l_coupler) * cos(l_coupler*beta_cp); //t_cp = cos(kappa_coupler*l_coupler) * limexp(1j*l_coupler*beta_cp) t_cp_r=cos(kappa_coupler*l_coupler) * cos(l_coupler*beta_cp); t_cp_i=cos(kappa_coupler*l_coupler) * sin(l_coupler*beta_cp); phi=phi_bi-V(Nint); if (phi<0) phi=0; W=alpha_wd * sqrt(2.0*eps*phi/(`P_Q*N_avr)); Wdp=N_D * W/(N_A+N_D); Wdn=N_A * W/(N_A+N_D); xlength=rib_width/2; for (i=0; iWdp) begin pp[i]=N_A; end else begin pp[i]=0; end pn[i]=pn00*(exp(`P_Q*V(Nint)/(`P_K*$temperature))-1)*exp(-(x[i]-Wdn)/Lp)+pn00; if (x[i]>Wdn) begin nn[i]=N_D; end else begin nn[i]=0; end if (np[i]<0) np[i]=0; if (pn[i]<0) pn[i]=0; end for (i=0; i<2*xnum; i=i+1) begin if (ilam_end) begin $display("Warning: lam=%f is out of range [%f,%f]",lam*1e6,lam_start,lam_end); end if (Wdp*1e6width_end) begin $display("Warning: Wdp=%f is out of range [%f,%f]",Wdp*1e6,width_start,width_end); end neff_phaseshift = $table_model(Wdp*1e6, lam*1e6, neff_widthtable_ps, neff_lamtable_ps, neff_table_ps, "3L,3L"); end if (read_table_wg == 0|| lam_old==0 ) begin read_table_wg=1; end if (read_table_wg == 1) begin wg_file=$fopen(neff_wg_filename,"r"); if (wg_file==0) begin $display("Error: cannot open wg_file %s",neff_wg_filename); $finish; end $fscanf(wg_file,"%f",lam_start); $fscanf(wg_file,"%f",lam_end); $fscanf(wg_file,"%d",lam_num); for (i=0; ilam_end) begin $display("Warning: lam=%f is out of range [%f,%f]",lam*1e6,lam_start,lam_end); end neff_waveguide = $table_model(lam*1e6, neff_lamtable_wg, neff_table_wg, "3E"); end beta_wg = 2.0*`M_PI*neff_waveguide/lam; beta_ps = 2.0*`M_PI*neff_phaseshift/lam; k_wg_r=-alpha_phaseshift_ref; k_wg_i=beta_wg; k_ps_r=-alpha_phaseshift*alpha_absorp; k_ps_i=beta_ps; er = phaseshift_ratio*2.0*`M_PI*r*k_ps_r+(1.0-phaseshift_ratio)*2.0*`M_PI*r*k_wg_r; ei = phaseshift_ratio*2.0*`M_PI*r*k_ps_i+(1.0-phaseshift_ratio)*2.0*`M_PI*r*k_wg_i; p_mr_r = limexp(er)*cos(ei); p_mr_i = limexp(er)*sin(ei); c1r = t_cp_r + p_mr_r*((k_cp_r*k_cp_r-k_cp_i*k_cp_i)-(t_cp_r*t_cp_r-t_cp_i*t_cp_i))-p_mr_i*(2.0*k_cp_r*k_cp_i-2.0*t_cp_r*t_cp_i); c1i = t_cp_i + p_mr_i*((k_cp_r*k_cp_r-k_cp_i*k_cp_i)-(t_cp_r*t_cp_r-t_cp_i*t_cp_i))+p_mr_r*(2.0*k_cp_r*k_cp_i-2.0*t_cp_r*t_cp_i); c2r = 1.0-p_mr_r*t_cp_r+p_mr_i*t_cp_i; c2i = p_mr_r*t_cp_i+p_mr_i*t_cp_r; cr=(c1r*c2r-c1i*c2i)/(c2r*c2r+c2i*c2i); ci=(c1i*c2r+c1r*c2i)/(c2r*c2r+c2i*c2i); E_out_R = cr*E_in_R-ci*E_in_I; E_out_I = ci*E_in_R+cr*E_in_I; V(Opow) <+ E_out_R*E_out_R+E_out_I*E_out_I; V(Ophase) <+ atan2(E_out_I,E_out_R)*360.0/(2*`M_PI); V(Olam) <+ V(Ilam); lam_old=lam; width_old=Wdp; end endmodule