Lasers and Side Emitting Fiber Optic Cables

[JKaras]

Hello Everybody,

We would like to use lasers to illuminate 3mm side-emitting fiber for a
large scale light installation.
Our experiments with cheap laser pointers were unfortunately unsatisfactory
due to low quality lasers used in those devices.

It would be great to get help from this list on how to get started without
spending thousands of dollars.

Here are a couple of questions:
Can we go brighter than 5mW without melting the fiber?
Any sources for diode-fiber coupling ready made parts that would allow us to
go brighter?
Should we source laser diodes from an electronics supplier like DigiKey with
or without driver circuits and tweak the voltage to test different
brightness levels?
Has anybody on this list ever done this and what was your experience?
How long can light emitting lasers stay on before they exceed there usage
and burn out?
Can we run them 24 hours a day?

We have a decade of experience with LEDs, driver circuits, DMX control, etc
but are new to lasers (see Paramedia).

Any advice would be highly appreciated.

Thank you for your help in advance!

 

[bobhaha]

Can we go brighter than 5mW without melting the fiber?
Yes you can... you can get up in the Watt range without melting the fiber (We are talking about glass fiber right?)

Any sources for diode-fiber coupling ready made parts that would allow us to go brighter?
What fiber are you using? If you can connect it to the standard TOSLink connector there are couplings available online.

Should we source laser diodes from an electronics supplier like DigiKey with or without driver circuits and tweak the voltage to test different brightness levels?
It depends on your needs... what wavelength do you want? What kind of beam profile are you looking for? What fiber are you using? All these questions need to be considered before finding a supplier.

Has anybody on this list ever done this and what was your experience?
Yes people on this forum have worked with fiber optics and laser diodes before. Do a bit of searching on the forum.

How long can light emitting lasers stay on before they exceed there usage and burn out?
It depends on the output current you run the laser at. Usually they are in the 100,000 hour range if driven to manufacturers standards. For a more indepth explaination refer to this PDF

Can we run them 24 hours a day?
Yes....

 

[Cyparagon]

Where are you buying your fiber?

 

[JKaras]

We use plastic fiber. Not sure where we got it, the cheapest supplier we could find, I'm sure. It works great with high brightness LEDs. We just want brighter and less fallout.

We want to be able to use all different wavelengths. Leaning more towards reds and greens.

 

[BShanahan14rulz]

I would stick to using LEDs and fiber injection optics built for LEDs. Injecting laser into glass fiber at its simplest is just butting the pollished face of the fiber against the face of the laser. For LEDs, I bet you could get away with finding a refractive index matched optical epoxy and maybe even mount the fiber optically to the silicone dome of the LED.

Also, experiment with texturing the "fiber" further away from the source end, maybe that can even out how far down the fiber the light is emitted.

http://www.fraen.com/images/LensArrayOnBlack.jpg < here's some fraen fiber couplers
http://www.fraensrl.com/images/FFLI_Datasheet.pdf

 

[JKaras]

Heya,

We did more experimenting over the weekend and decided to slightly switch course. Lasers in combination with fiber-optics quickly becomes quite expensive considering that we'd require at least 200 laser modules with optics and fiber for the kind of large-scale installation we want to do.
By simply using cheap 5mW laser modules, mounting them horizontally safely above eye level at 8 ft and having the beam bounce off small 6x6 inch vertically suspended glass plates we were achieving very nice primary laser points on the glass plates and reflected and moving secondary/tertiary/etc points on the walls.

We were also able to control the brightness of the laser modules by simply connecting the input voltage to a DMX driver-controller system which opens up basically the same economic off-the-shelf control options as with LEDs.

The only question now for larger test set-ups is where to get economic 5mW laser modules possible in red, green and blue (450nm preferred).
Can you recommend any US based supplier with good quality 5mW laser modules under $10 a piece?

Thanks as always!

Jason & Team