Fiber Coupled 520nm diode and others between 420-440nm

[Singlemode Laser]

Will take a look for those! That would do the job nicely.

MM fiber is fine for pumping, as you said, more about the beam shape than anything else. Keep in mind the big FC pumps use diode arrays coupled to fiber bundles (19 emitters/19 fibers) and those work well.

I realize now that I forgot to paste the link for a such adapter. Here it is:


https://www.lasertack.com/en/adapter-for-fiber-collimators

I am sure that you can also find similar ones somewhere else.

I know how they couple these bars. Saw it multiple times myself and I am still impressed. With kW of optical power every dust particle is a burning fireball and still, it works like a charm!

Hope it will help you to improve the stability of your setup.

Singlemode

 

[diachi]

I realize now that I forgot to paste the link for a such adapter. Here it is:


https://www.lasertack.com/en/adapter-for-fiber-collimators

I am sure that you can also find similar ones somewhere else.

I know how they couple these bars. Saw it multiple times myself and I am still impressed. With kW of optical power every dust particle is a burning fireball and still, it works like a charm!

Hope it will help you to improve the stability of your setup.

Singlemode

Excellent, thanks for the link! Exactly what I was looking for! :beer:

I wonder how well a NUBM44 would couple into one of those... Could be nice with a collimator on the end of the fiber...

Yes, impressive how they couple the arrays, very fine work required. Very easy to burn the fibers with the powers that are often involved.

 

[paul1598419]

Do you expect that a NUBM44 would actually burn the fibers in a MM fiber optic cable? Seems highly unlikely to me, but you may know something I don't. :thinking:

 

[diachi]

Do you expect that a NUBM44 would actually burn the fibers in a MM fiber optic cable? Seems highly unlikely to me, but you may know something I don't. :thinking:

Not as long as the face of the fiber is kept free of contaminants and you used a large enough diameter fiber. Power loss would likely be fairly significant. Would be interesting to experiment with, it'd result in a nice round beam, that's for sure.

 

[Singlemode Laser]

Do you expect that a NUBM44 would actually burn the fibers in a MM fiber optic cable? Seems highly unlikely to me, but you may know something I don't. :thinking:

Like diachi said, it depends on the beam profile and the fiber diameter. I work almost exclusively with single mode fibers. Their core diameter is only some micro-micro meters big, but the basic rule that applies to all fibers is:

Light that is not coupled into the fiber is focused at the fiber end (called fiber ferrule) or is reflected. The first can burn your ferrule and also the embedded fiber if there is some dirt or other particles. The second can damage you diode if the reflected light is to strong. So always start coupling at low powers, optimize the coupling first and increase the power a bit after that. Repeat until you reached the max input power.


The second rule is:

The power per solid angle can never be increased, only preserved or reduced (follows from energy conservation). That is the reason why a larger beam (smaller intensity) has a lower divergence if you use proper optics.

That is why single-mode diodes exist at all. Their mode is almost a pure Gaussian beam with the smallest possible divergence. Visibility scales with the square of beam distance but the beam size just linearly. So the most amount of photons reach you (or somebody else) if you use a pure Gaussian beam.

However a lot of applications do not require single mode beams or fibers. In this case multi mode fibers are a great way for spatial filtering the beam and to connect it's output everywhere you want without free optical paths and almost always some mirrors. That is great for high power pumping beams, industrial applications and a lot more.

Singlemode

 

[paul1598419]

I actually already knew about the angle the beam must be aligned to in order to couple light into an optical fiber. I always called the end the facet, but ferrule works just as well as it means a small ring. And, of course at high powers one needs to keep them free from any kind of debris. I guess I misunderstood that diachi wasn't specifically talking about coupling an NUBM44, but just high powers. To me, 7 watts isn't exactly high power. But, kW is.