Parameters
wx : half width of the waist in the XZ plane
wy : half width of the waist in the YZ plane
wf : mode radius of the fiber optic
L : distance between the two lenses
T : total transmission coefficient of the system
fi1 : back focal length of the first lens
fi2 : back focal length of the second lens
e : distance between the respective waists of the incident and refracted beams
C : coupling ratio