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Dear community,

I wanted to simulate the collimation of laser light that comes out of a single-mode fiber. 
Wavelength = 1550 nm;
beam waist at fiber = 5,05E-3 mm;
In more details, my goals are:

(i) collimate the laser light and make sure that the beam width (i.e., the diameter) of the light after the collimation lens is within 3.2 and 4.0 mm. This was my primary concern.
(ii) collimator lenses are often aspheres, with a conic constant and a 4th-order term filled in. I did not do any optimization for these values first, only when I came across the notion that Gaussian Beam Propagation (GBP) and Physics Optics Propagation (POP) were different from each other. That’s also my question about.

 

Since, I first wrote down my question in word, it seems that it was not copied well from word to here. It complains that I have reached the maximum number of characters of 5000, but in word, the number of characters is not beyond that. I have therefore, attached my question as a pdf. In the meantime, I'll try to fix it. 

 


Hi Monique,

If you are using an aspheric lens to collimate your beam, then I would rely on the POP results to determine beam size versus propagation distance.  The paraxial Gaussian beam analysis only takes into account the base radius of curvature for any lens surface and ignores the aspheric terms -- see the brief discussion of “paraxial rays” in the “Conventions & Definitions” section of the help documentation:

 

Regards,

Jeff


Dear Jeff Wilde, 

Since I lacked a bit of confidence on these matters, I am happy to read your answer as it is a confirmation of my thoughts on it. 
Thank you for your time to reply!

 

Best regards, Monique


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