# What light source would put the most broadband white VIS/NIR light into a single 0.4 mm fiber?

**URL:** <https://boards.straightdope.com/t/what-light-source-would-put-the-most-broadband-white-vis-nir-light-into-a-single-0-4-mm-fiber/614565>\
**Category:** Factual Questions\
**Created:** [March 2, 2012, 5:18pm UTC](https://boards.straightdope.com/t/what-light-source-would-put-the-most-broadband-white-vis-nir-light-into-a-single-0-4-mm-fiber/614565 "2012-03-02T17:18:44Z")\
**Posts on this page:** 1\
**Page:** 1

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**Author:** ![Napier](https://avatars.discourse-cdn.com/v4/letter/n/ce73a5/32.png) [@Napier](https://boards.straightdope.com/u/Napier)\
**Post date:** [March 2, 2012, 5:18pm UTC](https://boards.straightdope.com/t/what-light-source-would-put-the-most-broadband-white-vis-nir-light-into-a-single-0-4-mm-fiber/614565/1 "2012-03-02T17:18:44Z")

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I have a system that relies on white light entering through a single optical fiber of 400 um diameter. It currently has a NA of 0.22 but this could change if I want. I have an old Oriel tungsten source currently illuminating the fiber and have played around a bit with fiber placement, but it looks like there’s too little light for the system to work well. Especially, I’d like it to work out in the infrared to a micrometer or two, and the present system roughly falls off in a pretty straight line from 700 nm to 1600 nm.

It seems like the point here would be to get the closest approximation to the hottest blackbody possible, like maybe a carbon arc lamp or a zirconium one, or else to get the most intense plasma source possible. Considering the fiber size, I bet I’m not talking about high power or bright light, but rather, _intense_ light. But, then, I hear there are new white LED fiber optic sources, and even found something a little confusing about a “white laser”.

Nobody’s sales literature seems to say how many watts of light can get forced into this little dot of a fiber.

Any advice? Thanks!