wl0 1.55[um] Design wavelength
w_core 0.2[um] Core width
w_clad  10*w_core Cladding width
r0 4*wl0 Radius of curvature
dx 3.5833*w_core Separation between waveguides
lda0 wl0 Wavelength
f0 c_const/lda0 Frequency
n_core 2.5 Core refractive index
n_clad 1.5 Cladding refractive index