Hello Christopher,
By “faces the z-direction” I am going to work under the assumption that you mean the elliptical cross section is in the XY plane and the waveguide runs along the z axis.
The best way to set this up is to add a fiber profile through Profile Designer with your desired major and minor axis. then create a linear waveguide along z and assign the fiber profile to this waveguide. I have attached a picture of a design that has the elliptical waveguide you are referring to and the waveguide I am describing on the left.
Is this what you are looking for?
Scott
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