Need to get blue light into fiber optic cable

[dullard]

I need to get light into eight different fiber optic cables (typically blue at ~470 nm). Currently, I have this LED light source. However at a cost of $499 each for one LED or $699 for dual LEDs and $100 to change the LED color, it is cost prohibitive. It'll cost me over $3k to do it.

So instead, I bought some ~$1 blue LEDs and machined a part to hold the fiber optic cable up close to the LED. Unfortunately, I get only one fourth the brightness I need with this method.

[*]I considered brighter LEDs, but I haven't found any yet. They certainly should exist. Maybe someone here knows of a good LED supplier.
[*]I considered Laser Diodes, but for blue I haven't yet found anything inexpensive. Any idea on where to find cost effective blue laser diodes?
[*]I considered lenses to focus the LED light onto the fiber optic cable. But I haven't pursued this path much so far. Would that help significantly? Any idea on where to get good inexpensive lenses?
[*]Are there any other off-the-shelf products that you know of that lets you shine an LED onto a fiber optic cable?

 

[pontifex]

what exactly are you trying to make?

 

[spidey07]

what is the core size of the fiber and has it been properly cut/polished?

I would think you could get what you need in an LED. Make sure there is no light leaking and the fiber/led are aligned well. That junction is very critical in overall output.

 

[djheater]

When I was looking into LED's a few years ago. I was very satisfied with what Luxeon was offering.

I didn't see a Lumen rating on what you linked, so no idea if they're competitive.

 

[Rubycon]

Blue laser diodes are at a premium and a blue DPSS laser module is going to be out of reach of your budget unfortunately. A 5W royal blue luxeon emitter has enough power most likely, but beam delivery and shaping is going to be another thing altogether. :Q

 

[Jeff7]

20 lumens
Should be a good bit brighter than the little 300mcd thing you used before.

 

[dullard]

Originally posted by: pontifex
what exactly are you trying to make?

A fiber optic octopus, of course.

No, it is a research project for the university. I need to shine directed light into a chamber at akward angles (and each light needs to be independantly operated). So fiber optic cables are about the only possibility.

 

[dullard]

Originally posted by: spidey07
what is the core size of the fiber and has it been properly cut/polished?

I would think you could get what you need in an LED. Make sure there is no light leaking and the fiber/led are aligned well. That junction is very critical in overall output.

200 micron diameter fiber. Cut and polished at a factory, so I assume it is done properly.

Originally posted by: djheater
When I was looking into LED's a few years ago. I was very satisfied with what Luxeon was offering.

Thanks, I'll look into it.

Originally posted by: Jeff7
20 lumens
Should be a good bit brighter than the little 300mcd thing you used before.

I'll look into that too.

 

[Rubycon]

Does the light source have to have a spectral center at 470nm with semi-monochromatic properties of light emitting diodes? If not a filtered white light source may be plausible.

 

[dullard]

Originally posted by: MS Dawn
Does the light source have to have a spectral center at 470nm with semi-monochromatic properties of light emitting diodes? If not a filtered white light source may be plausible.

I have briefly thought of that too. No, they don't need to be centered exactly at 470 nm, a few nm off and I'll be fine. A narrower band is prefereable. Then there are plenty of bandpass filters that should work, I've found some for ~$50 each. LEDs are nice in the fact that I have the right electrical signals already ready, they are long lasting, and they are low power. But those are all obsticles that can be worked around.

 

[Rubycon]

Do you need blanking capability as well? LED's and lasers (best) are the fastest. I suppose a chopper will work with a halide source but if we're talking about stuff for an optical bench, it's quite (ridiculously) expensive.

A 488nM argon will make a nice pretty blue light but they are quite hungry all the way around.

 

[dullard]

After looking at the links above, I liked the LCK304BCT4 from LCD-LED.com It is the exact same as the LED I already use, but it is 13 times brighter and has a narrower viewing angle. Net effect will be ~20 times brighter into the fiber optic cable. There is a 5mm version as well that is slightly brighter, but the larger diameter means roughly the same amount of light would enter the LED fiber unless I get a lens or something similar to focus the light.

The 5W Prolight light looks promissing too. I like the ability to have multiple different lights in the same package. However, I'd need to look into a way to focus the large 140° viewing angle back down onto a fiber optic cable.

Originally posted by: MS Dawn
Do you need blanking capability as well? LED's and lasers (best) are the fastest. I suppose a chopper will work with a halide source but if we're talking about stuff for an optical bench, it's quite (ridiculously) expensive.

A 488nM argon will make a nice pretty blue light but they are quite hungry all the way around.

Now you are getting a bit above my head, I have little experience and no education in optics.

What is blanking? What is a chopper? Is a chopper just a device that rotates with holes to turn the light on/off? What is an optical bench? Is there a good book/website that can introduce me to these ideas?

 

[Mark R]

One of the advantage of the luxeon sources, is that they have readily available collimating optics, available down to 10 degrees.

The combination of a 3 W luxeon source and collimator, should give you satisfactory luminous intensity.

 

[Rubycon]

Blanking is the ability to turn the laser on and off at very fast rates. We use it in our raster capable displays for special effects on the stage and beam shows to create 3D floating effects, etc.

Choppers are very similar to what you describe. They are used for sources that are fixed CW that cannot be blanked with an external circuit.

The optical bench is a very heavy and rigid table surface with holes (looks like perforated board) for mounting fixtures, C-mounts, etc. for objects in the beam path.

This site has lots of information on lasers and optoelectronics in general. It's easy to get lost for hours there.