# Tapering in bent waveguide

Dear Lumeral team,

I am interested to tapered the bent waveguide, is it possible kindly let me.
see the below figure

I want to design the four yellow circled bend portions with tapering from 600nm to 80nm (in both directions width and height).
Is it possible? if so kindly let me how to do in directional coupler.

Hi, Nanda

I think the most convenient way is to dray the tapered structure in a GDS editor (klayout, for example) and import it to where you need it.

Nanda,

I think, here is the link on the topic to some extent related to your question:

1 Like

Hi,
by using the script in the attached link, I can make the sin waveguide or from the structure we can make bend waveguide.
but I want to taper the waveguide from one end to another end. I donâ€™t have any idea about this kindly let me

Nanda,

Here is my example of the cosine bend:

deleteall;
clear;

set(â€śnameâ€ť,â€śTaperedCosineâ€ť);

w_wide = 101e-6;
w_narrow = 0.5
1e-6;

N = 3e1;

w = linspace(w_wide, w_narrow, N);

x0 = 0;
xend = 1001e-6;
A = 50
1e-6;

x = linspace(x0,xend,N);
deriv = -pi/xendAsin(pix/xend);
x1 = x - w
deriv/2/sqrt(1+deriv^2);
y1 = Acos(pix/xend) + w/2/sqrt(1+deriv^2);

x2 = x + wderiv/2/sqrt(1+deriv^2);
y2 = A
cos(pi*x/xend) - w/2/sqrt(1+deriv^2);
x2 = flip(x2,1);
y2 = flip(y2,1);

v= [x1, y1; x2, y2];
set(â€śverticesâ€ť,v);
set(â€śz minâ€ť, -0.11e-6); set(â€śz maxâ€ť, 0.11e-6);

which gives the following profile

3 Likes

thank you very much your help, the structure will help me a lot.