w 2[um] Waveguide width
w_tot 30[um] Total waveguide width
d0 2*lda0 Initial straight waveguide
dy_bend 0.6*w_tot Total displacement in y-direction at S-bend
r0 100[um] Bend radius
alpha acos((r0-dy_bend/2)/r0) Bend angle
dx_bend 2*r0*sin(alpha) Total length in the x-direction for S-bend
d_cpl 90[um] Length of straight directional coupler waveguides
d_dc 2*dx_bend+d_cpl Total length of directional coupler
d_mz 100[um] Length of Mach-Zehnder waveguides
dy_wg 3[um] Distance between directional coupler waveguides
d_cc dy_wg+w Directional coupler core center separation
d_pcc 2*dy_bend+d_cc Port core center separation