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FrozenGate by Avery

Fiber Optics

Do you still lose A LOT of power even if you focus the laser beam to nearly a point with a lens into the fiber or does the loss occur in the fiber?
 





Im guessing the more expensive cables that use glass rather than plastic would be better suited for 445nm. Also, since these are supposed to work on total internal reflection, shouldnt that mean we dont need to worry about burning up the interior of the cable, but rather just the faces at either end?
 
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all the fiber mentioned in this thread is glass except for perhaps the large toslink fiber.

Only have to worry about the ends, hence the polishing as an attempt to reduce losses. Obviously, the better it's polished, the lower your losses. Also, the less you bend the fiber, the lower your losses.

Output isn't collimated, you need an aspheric to project the image of the fiber face, a good enough approximation of a point source, though not as good as a laser's emission area on the die facet.

Power Handling Recommendations
50um should be enough for 5W according to one of google's results

the smaller the fiber, the easier it is to focus it to very low divergence.
 
Anyone trying to focus a multimode laser diode into a fiber is going to experience large losses.
 
As in all the above posts, I did notice the power seemed lower through the fibre. I'm getting a LPM so I'll do some tests when I get that.

If anyone is interested, Fibre patch leads though our normal supplier are $AU21.50+GST for dual 1m SC patch leads (two fibers) and MTRJ 1m leads are $AUD15.50+GST (again dual fibres). The SC ones can be split into two fibers but the MTRJ have both fibers terminated in one connector as in my photos above.

The fibre we use is 6.25um multi mode glass (I think I said 62um in an above post).
 
Anyone that wants to play with glass or plastic fiber shoot me a pm(free). I gots lots.
*** photo id for the glass*** it's potentially dangerous due to the fact it can break and find its way into your eye or take a red blood cell raft ride to your heart
 
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Cheech said:
it's potentially dangerous due to the fact it can break and find its way into your eye or take a red blood cell raft ride to your heart
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That's why I only use terminated sheathed patch leads lol.
At least you know the faces are flat and properly polished too.

Mind you raw fibers are fun in that you can see the beam inside them...
 
I have a question on fiber. What kind would I use for a 12-40W 808nm FAP? I recently discovered something about fiber and high output lasers.

So no one else runs into this. I had a spare piece of fiber with a fitting on the end that mated with my FAP. I decided to plug it in and see if I could direct the output. When I turned on the laser, I got a flash and then smoke from the output end of the laser. From what I can tell I must have melted the fiber either in the cable or inside the laser itself.

Don't try this!!;) The laser no longer works, just sparks at the end a bit and smolders.(I don't try anymore)
 
Sounds like the fiber surface may have reflected too much light back into the die and killed it, kind of like when you reflect the beam of a diode laser back into itself off a mirror.
 
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if you don't polish and clean those ends, then the light gets absorbed by the contaminants, and when something absorbs several watts in a small area, I can imagine there might be sparks ;-) Hopefully the diode is fine and there might just be some optic that need replacing
 
did the other end of the fiber have an end on it. I wonder if it was not terminated in some kind of "connector/end" that maybe the photons reflected back at the die when they hit the jagged unmade end of glass. Kinda like "you'll shoot your eye out" in that christmas movie.
 
Apocalypse said:
Hello all,

Is it possible to use a fiber to improve the beam specs of something? Say, turn a 445nm multimode or a 635nm multimode into a single mode output or something closer to a single mode output? I know I need something to focus the original laser beam into to the laser fiber and something to collimate it at the other end.

Thanks!
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I suggest that you shou use the lens to focus the light in to the fiber,instead of the one who said that to use a acrylic light pipes ,a trong heat will sure brun it down.
about the lens ,you can chose a glass materials , espectial a aspheric lens not an ordinary one,,,,of course ,the cost will be high also...:D:D
 
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