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Rotation of non-symmetrical ZBF

  • 7 September 2021
  • 5 replies
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Dear all,

I have a ZBF which is rotational non-symmetric. After I propagate the mode profile through my rotational non-symmetric system, I couple into a single mode fiber. Now, I want to examine how the coupling efficiency changes due to a rotation of the Input-ZBF (simulated data of a waveguide). 

I tried adding a Coordinate Break after the Start-Surface, but nothing happens when I change the Tilt about Z on the CB. I guess it has something to do with the rotation matrix, but there must be a way how I can analyze this tolerance. 

Thank you in advance.

Kind regards

Katrin

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Best answer by Sandrine Auriol 9 September 2021, 15:37

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5 replies

Userlevel 6
Badge +2

Hi Katrin

The ZBF input beam will be centered and perpendicular to the chief ray (at the defined field and wavelength). So a coordinate break won’t affect that definition.

To test the effect of a rotation of the input ZBF, I think the easier would be to define a new field (that would correspond to a Z rotation) and set this field as the reference in POP.

Let us know how it goes.

Sandrine

Hello Sandrine,

I tried to use the field definition to rotate my input ZBF. Am I correct that I have to adjust the rotation of the tangetial plane by using “TAN” in the field editor? When I do that, I unfortunatley do not have any effect on the POP results. 

Kind regards

Katrin

Userlevel 6
Badge +2

Hi Katrin

Sorry for the late reply. I have removed the “Best Answer” tick because otherwise we don’t get notified.

To adjust the rotation, I would simply use the X and Y field coordinates, so for example if you have a field at X=0mm, Y=10mm, I would create a new field X=7.07mm and Y=7.07mm to make a rotation.

Would that work for you?

Sandrine

Hello Sandrine,

I tried using the fields for a rotation, but unfortunatley it seems to have no effect. In the picture you see my attempt. I defined several fields at different positions where I would expect a significant change in the coupling efficiency, but this can not be seen in the POP operands that calculate the receiver coupling efficiency in the merit function. 

Do you have an idea what went wrong?

Kind regards

Katrin

 

Userlevel 6
Badge +2

Hello Katrin

I’m not sure without seeing your file, but maybe 1st check the position of the receiving fiber:

I did a quick test on one of our examples and it seems to behave correctly.

If needed email support@zemax.com to open a ticket with us and share your file

Sandrine

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