Fiber launching these 445nm diodes

[CrazyMonkey]

I think Andy is right.
Either really small fiber, or a huge beam, or horrible divergence.
the light does not come out parallel(ish) like in a laser cavity.(including diode)

But if you wanna focus it and burn crap, that's fine, hehe.
Also ok if you want to pump a crystal, like ktp or yv04.(with 808)

Has anyone here actually made a decent beam with a fiber here?

[andyf97]

I think Andy is right.
Either really small fiber, or a huge beam, or horrible divergence.
the light does not come out parallel(ish) like in a laser cavity.(including diode)

But if you wanna focus it and burn crap, that's fine, hehe.
Also ok if you want to pump a crystal, like ktp or yv04.(with 808)

Has anyone here actually made a decent beam with a fiber here?

I have had a reasonable beam using an OPSL and a 25um fiber but after that it was only because I had to do it for an effect with a dancer.

It's quite tricky and costly in power loss and optical requirements.

Certainly not worth trying for these blue diodes without some initial beam preparations.

Might be worth putting the diode first in a 200um to at least round it but then what.

Fibers have one quite good benefit if you put RGB into it, each color comes out of the fiber with very similar specifications and perfect for mixing.

Here's a photo of some tests we did using a 50um fiber connected to a 5W RGB.

http://www.lasershows.ro/site/galler...p=IMG_2604.jpg

[mixedgas]

I am also working on fiber coupling these, using ball and half-ball lenses. I'm shooting for 200 micron .37NA fiber first, and hoping for 100 micron 0.22NA eventually. Now I have a question: What's the best way to combine multiple diodes in a fiber launched system? Would a fiber bundle (say 10 fibers 200 microns each with one diode per fiber, together in an SMA connector) provide sufficient brightness to collimate well, or would the resulting beam be unusable? Would it be more useful to try using cylindrical lenses or prisms to couple an entire array of multiple diodes into a single fiber, as is sometimes done with IR bars? This is a problem I've never solved before in real life.

Do me a favor, when you refer to a fiber could you refer to the whole size, for example, common comms fiber is 62.5/125 core/cladding diameters. Or please say 100 uM core?

Steve

[CrazyMonkey]

Oh so pretty! I have an urge to put a prism in the beam.
Am kinda surprised the colors stayed together so well, unless you used
achromatic lenses.

I have had a reasonable beam using an OPSL and a 25um fiber but after that it was only because I had to do it for an effect with a dancer.

It's quite tricky and costly in power loss and optical requirements.

Certainly not worth trying for these blue diodes without some initial beam preparations.

Might be worth putting the diode first in a 200um to at least round it but then what.

Fibers have one quite good benefit if you put RGB into it, each color comes out of the fiber with very similar specifications and perfect for mixing.

Here's a photo of some tests we did using a 50um fiber connected to a 5W RGB.

http://www.lasershows.ro/site/galler...p=IMG_2604.jpg

[ogoun]

I probably should have indicated that my primary interest in these 445nm (and most other) lasers, is for scientific purposes, mainly as coherent light sources of relatively monochromatic output.

Power output is not my top priority, and i would not be concerned with losing 50% of a single 445nm laser diode's output, since that still leaves over 400mw left (!).

The fiber patch lead is specifically a very narrow diameter single mode fiber (dont have the specs handy). It is used purely as a convenient way to couple a laser light source to a microscope vertical illuminator.

The output beam characteristics directly from the fiber arent great, of course. That's why we use a second fiber launcher (with female SMA connector) at the microscope vertical illuminator end, to re-collimate the beam somewhat. It is still far from what anyone here would want to use as a "fun" output, though. Spot size is nicely round, and about 20mm diameter at 50cm, after passing through the second fiber launcher. Works excellently with the microscope, though.

While I enjoy reading about the wonderful exploits of my fellow members here, and I think the images and videos posted are great, I am unlikely to ever need a laser projector, or be using lasers in an entertainment capacity.
I confess, though, I had fun a while ago with one of our prototype laser hosts, when I was first able to burn a hole in a piece of paper at 1 metre range!

The best thing about these forums for me is the energetic and active discussion and development of things like host electronics, optics, heatsinking, TEC controllers, etc. Kudos to those who take in ideas from here and elsewhere, and then put together reliable cost-effective solutions.

Cheers,

Pete

[jaycey]

A cheap experiment for someone?

http://cgi.ebay.com/SMA-Fiber-Coupli...item335e5ba313

http://cgi.ebay.com/SMA-Fiber-Optic-...item335e5c45ca

[ogoun]

Those are the launchers we are using... They look good so far.

[mpoulton]

I probably should have indicated that my primary interest in these 445nm (and most other) lasers, is for scientific purposes, mainly as coherent light sources of relatively monochromatic output.

Power output is not my top priority, and i would not be concerned with losing 50% of a single 445nm laser diode's output, since that still leaves over 400mw left (!).

Some people are reporting that these lasers will run in TEM00 at low currents (maybe 180-250mA). That might be useful for what you're doing. It will certainly make coupling into a small fiber easier.

[mpoulton]

Do me a favor, when you refer to a fiber could you refer to the whole size, for example, common comms fiber is 62.5/125 core/cladding diameters. Or please say 100 uM core?

Steve

Is the cladding diameter relevant to the optical characteristics? The fiber in question is 200u core / 230u cladding.

[ogoun]

Those are the launchers we are using... They look good so far.

Forgot to mention.. They sell the matching single mode fiber patch cables for these as well...

Cheers,

Pete