Re: 405 laser intensity at the objective is 0.15% of actually intensity ... is this normal?

Posted by Emmanuel Levy on
URL: http://confocal-microscopy-list.275.s1.nabble.com/405-laser-intensity-at-the-objective-is-0-15-of-actually-intensity-is-this-normal-tp7587264p7587286.html

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Dear Pete,

I was wrong, we actually have a single mode and not a multi-mode fiber. May
I ask what is to be expected in terms of coupling efficiency for single
mode fibers?

Thank you for your input,

All the best,

Emmanuel



On 6 September 2017 at 22:15, Peter Brunt <[hidden email]>
wrote:

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> *commercial (non-commercial) post*
>
> Hi Emmanuel
> Are you running your lasers at full power?  What combiner are you using?
> I can't comment so much on the power you have at your objective but on your
> combiner side the values look low.  Going into a multi-mode fibre should be
> like a barn door for your lasers so if we imagine a ~5% (x2) loss due to
> combining optics and an ~80% coupling efficiency, you should still be
> getting a ~72% average coupling efficiency into the fibre.  It sounds to me
> like the setup may need to be realigned. If you still don't see an
> improvement then one other possibility is that the 405nm laser has degraded
> your fibre due to solarisation and the fibre needs replacing.
>
> I hope this helps.
>
>
> Kind Regards
>
> Pete Brunt
>