% directional coupler


dd=linspace(0.4,3,50);

for i=length(dd):length(dd)

index=[1.4,1.5,1.4,1.5,1.4];
thickness=[0.8,dd(i),0.8];
ml=multi(index,thickness);

% te eigenvalues at 955nm
i
nstart=index(1);
wl=1.2;
dump=1e-4;
acc=1e-12;
ev=mltevalue(ml,nstart,wl,dump,acc);

figure(1);
plot((dd(i))*ones(length(ev),1),ev,'or');
hold on;

end

yp=mltevector(ml,ev(1),wl);
ym=mltevector(ml,ev(2),wl);


return;

% dispersion relation

index=[1.4,1.5,1];
thickness=[0.8];
ml=multi(index,thickness);

% te eigenvalues at 955nm
nstart=index(1);
dump=1e-3;
acc=1e-12;
wll=linspace(0.2,2,100);

for i=1:length(wll)
  wl=wll(i);
  ev=mltevalue(ml,nstart,wl,dump,acc);
  figure(1);
  plot((1/wl)*ones(length(ev),1),ev,'or');
  hold on;
end





return

% define a multilayer

index=[1.4,1.5,1.45,1.38,1];
thickness=[0.8,0.4,0.6];
ml=multi(index,thickness);

% te eigenvalues at 955nm
nstart=index(1);
wl=0.955;
dump=1e-3;
acc=1e-12;
ev=mltevalue(ml,nstart,wl,dump,acc)

% plot it

mltevector(ml,ev(1),wl);