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How to increase fiber output power of LED array

tangzs
tangzs
@tangzs
3 months ago
198
1

There are 7 LEDs in TO39 packages with an outer diameter of 9.5 mm. Each LED has a lens at the light exit port, and after passing through the lens, the beam divergence half-angle is 7°. It is desired to couple the light from all 7 LEDs into a fiber bundle with a diameter of 2.5 mm. The fiber bundle consists of 93 uniformly distributed fiber cores, each with a diameter of 0.1 mm, and each fiber has a numerical aperture (NA) of 0.22. What is the best approach to maximize the coupling efficiency of the light from these 7 LEDs into the fiber bundle?

Discussion 1

ntap
ntap
@ntap
2 months ago

In your design, you start with NA of 0.12 and want to couple in a NA of 0.22. That leaves roughly a factor 2 for demagnification.

No matter what you do, I doubt you will couple more than the light of a single LED in your fiber bundle, as your source separation of 9.35mm will be translate to about 5 mm of image separation at the fiber bundle entrance plane. Of course, it depends on your LED specs. Size of active area, source angle before lens, color.

I would start with a singlet lens, custom apertures for the source and bundle and simulate light transmission efficiency, aiming for an optimum.

For sure there are people way more expert than me, and they might have a different take on the question.

Best of luck!

Nico

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