www.pudn.com > Slab.rar > group.m, change:2002-03-11,size:1518b


clear all; 
colortog; 
%Program for guiding created by symmetrical 3-slab layer 
er1=10.0362; %permittivity of cladding  
er2=12.0362;	%permittivity of core 
werd1=0.963067; % angular frequency times differential of permittivity with ang. frequ. in 1 
werd2=8.13536;% angular frequency times differential of permittivity with ang. frequ. in 2 
delteps=(er2-er1); 
Aw=0.5*(werd2-werd1)/delteps; 
theta=((1:650)-1)*(pi/2000); %optical guide width ranging from near zero to 0.35 pi 
Bw=0.5*(werd2-(werd2-werd1)*cos(theta).^2); 
V=2*theta./cos(theta); 
Rvmp=sqrt(er2-delteps*((cos(theta)).^2)); 
Rvmg=Rvmp+(Bw./Rvmp)+0.5*(1+Aw)*delteps*theta.*sin(2*theta)./((1 +theta.*tan(theta)).*Rvmp); 
Rvmgo=Rvmp+0.5*delteps*theta.*sin(2*theta)./((1 +theta.*tan(theta)).*Rvmp); 
vmp=1./Rvmp; % phase velocity/c 
vmg=1./Rvmg; % group velocity/c but with no material effects 
vmgo=1./Rvmgo;% group velocity/c with material effects 
nph=Rvmp; %phase index 
npg=Rvmg;	%group index with material effects 
npgo=Rvmgo;	%group index with no material effects 
figure; 
plot(V,vmp); 
axis([0 4 sqrt(1/er2) sqrt(1/er1)]); 
xlabel('Normalised frequency');ylabel('Phase Velocity') 
title('Phase velocity -Normalised frequency'); 
figure; 
plot(V,nph,V,npg,V,npgo); 
title('Group Index(magenta/blue) Phase(red)-Norm. Frequ.'); 
xlabel('Normalised frequency');ylabel('Index'); 
figure; 
plot(V,vmp,'r',V,vmg,'m',V,vmgo,'b'); 
title('Group Vel.(magenta/blue) and Phase Vel.(red)- Norm Frequ.'); 
xlabel('Normalised frequency');ylabel('Velocity/c');