gaussian beam propagation in waveguide

hello,

im unable to find the proper anallytical way to propagate a gaussian wave in a defined waveguide. is there a simple code to do that?

i need to propagate a wave in the waveguide and to find the propagation loss in dB after x length of waveguide.

i have the details about: wavelength, exact refractive index and size of the waveguide, and the electric field is defined as a gaussian beam field.

any idea of how to do that?

thank you

[Andicha Zain]

hello
do you know how to simulation coherence lenght gaussian beam