nzero.m

光子晶体光纤计算中相对抽运频率和四波混频效率的关系

%n段
clc;clear;
j=(-1)^.5
f0=193.5%THz
l=5
n=2^10
x=linspace(0,5,n)
f0x=f0-0.05*cos(2*pi*x/l)
fp0=linspace(-0.4,0.4,n)
fp=f0+fp0
fp0n=fp-f0x
c=3e5%nm/ps
la0=1550%nm
dDla=0.07
lap=c./fp%nm
lapr=12 %nm
lar=lap-lapr%nm
dbn=2*la0^4*pi*dDla*lapr^2./((lap.*lar).^2).*fp0n
alpha=0.2
l1=5/3
l2=5/3
l3=5/3
%eta=alpha^2./(alpha^2+db.^2).*(1+(4*exp(-alpha*l)*(sin(db*l/2).^2))/(1-exp
%(-alpha*l))^2)+j*db1
dbnn=int(dbn,0,y)
Acos=cos(dbnn)*exp(-alpha*y);
Bcos=sin(dbnn)*exp(-alpha*y);
AA=int(Acos,0,l)
BB=int(Bcos,0,1)
%eta=(abs((exp((-alpha+j*db1)*l1)-1)./((-alpha+j*db1))+exp((-alpha+j*db1)*l1).*(exp((-alpha+j*db2)*l2)-1)./((-alpha+j*db2))+(exp((-alpha+j*db1)*l1)+exp((-alpha+j*db2)*l2)).*(exp((-alpha+j*db3)*l3)-1)./((-alpha+j*db3)))).^2;
%eta0=(abs((exp(-alpha*l1)-1)/(-alpha)+exp(-alpha*l1)*(exp(-alpha*l2)-1)/(-alpha)+(exp(-alpha*l1)+exp(-alpha*l2))*(exp(-alpha*l3)-1)/(-alpha))).^2;
g=eta/eta0
plot(fp0,g)