When Should I use the Huygens Integral in the Fiber Coupling...
Authored By: Mark Nicholson
Huygens Integral
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Question: In the Fiber Coupling Efficiency Calculation under Analysis...Calculation...Fiber Coupling Efficiency, when should I use the Huygens Integral?
Use the Huygens Integral for the most accurate result. Its only disadvantage is speed, compared to the non-Huygens method. The non-Huygens method is somewhat faster. Therefore, test the results with the Huygens calculation on and off: if the coupling efficiencies are 'sufficiently' close (which is a judgment only you, the user, can make) then the non-Huygens result can be used with confidence.
You may also want to use the faster non-Huygens calculation for initial setup and optimization, and switch to the more accurate Huygens method for final optimization and evaluation.
There are cases where the full Huygens PSF is required. These cases generally have severe caustics or discontinuities in the wavefront. The recommended approach is to leave this option unchecked. If the fast raybased integration cannot be computed accurately, the fiber coupling will be zero and a warning will be printed which will recommend switching to the Huygens algorithm.