Where to buy 50um OD fiber?

[Vidal Wolf]

Use one of the really big flat diffraction gratings to help line up the fibers. The grating groves might help align the fiber strands.
I've got a huge flat grating I'd like to try it with.

[planters]

Anyone with a CNC mill could use a 50 um step and scratch out an array of parallel lines. I don't know if a diamond tip would give a relatively burr-free scrape in PTFE, but this material would allow you to follow up with a separable adhesive bonding of the fibers.

A laser drill could punch tiny vias in a sheet of material that you could then thread with the fibers. This assumes you can have some acceptable spacing between the fibers.

A more out of the box technique might be to obtain an imaging endoscope that already has an array of fibers, coherently parallel (that's why it transmits a meaningful image) and cut out a segment with a diamond saw. These endoscopes will be more and more available on the used market now that tiny, high resolution cameras, mounted at the working end are supplanting them.

[VDX]

... some years ago I've modified a CNC-mill (which normally runs with half-stepping and 12.5 microns step resolution) to 1/8 microstepping and milled parallel grooves with 15 microns spacing, 8 microns deep into PEEK with a standard 2mm-millbit, slanted by 45 degrees ... this was to make a special TC-sensor with parallelized platinum wires, forming two conducting 'sensor-curtains'-- worked perfect ;-)

Viktor

[mixedgas]

Use a multiaxis positioning stage and feed the fiber out a piece of hypo tubing about 2 to 2.5 times the OD of the fiber.
Lay the fiber into two parallel lines of epoxy.

Best done under a stereo microscope. How you scribe and break or burn thru the fiber to cut it is another mystery.

If it were me, I'd be going for self assembly, the fiber is precisely cut to length then fed into a groove milled in a jig resting on the substrate. Pushing it around with a probe or tweezers or feeding it out of hypo tubing gets it into position. The parallel sides of the jig constrain it in one axis. Have the jig walls be 100-200 microns wider then the cut strands. So just like childhood "Lincoln Logs" or hotdogs, it will tend to line up parallel by itself.

Steve

[planters]

I basically agree with VDX and Steve. I think the treatment of the ends depends on how this will ultimately operate. If a flat, plano surface is desired then a post assembly slice with a diamond saw and bulk polishing would work. This could also be applied to my endoscope slicing recommendation. These suggestions are now constrained by the limited information in the OP.

It seems like the result may be a little like a calcite crystal or an imaging light pipe which is also fabricated with fibers.

[mixedgas]

Attached is first page of relevant paper under educational use clause. Machida Endo Co. LTD. is still in business in Japan, so presumably they can still make the gratings. No method of assembly is listed in the paper other then stretching the fibers in a machine. As they make fiber bundles for a living, I'm sure they have a specialized machine for this.

Turns out this is a amazing grating for imaging and signal processing, and a X-Y (burst) version was made for tests as well.

High-Efficiency Fiber Grating for Producing Multiple Beams of Uniform Intensity...
Machida, Nitta, Seko, and Kobayashi Applied Optics Vol 23, No 2 15 January 1984.


Steve

[Junktronix]

This paper describes the monolayer of fibers as suspended over a hole in a substrate. The Machida gratings I have seen have the monolayer array sandwiched between 2 AR coated pieces of glass. It looks like there is adhesive saturating the fiber array, even though that would seem to change the behavior of the array and be subject to damage from higher power lasers.

The grating I got from Aje is about 5mm wide and I count 97 fibers so it's definitely 50um fiber. I now officially have infinity+1 projects so it'll be a while before I have a chance to try and form a monolayer of my own. My offer stands to send an envelope of 50um fiber strands to anyone who wants to give it a shot and is willing to share their results. The paper notes that the construction method is similar to that for imaging fiber bundles. Perhaps some research into that will prove interesting.

[mixedgas]

This paper describes the monolayer of fibers as suspended over a hole in a substrate. The Machida gratings I have seen have the monolayer array sandwiched between 2 AR coated pieces of glass. It looks like there is adhesive saturating the fiber array, even though that would seem to change the behavior of the array and be subject to damage from higher power lasers.

The grating I got from Aje is about 5mm wide and I count 97 fibers so it's definitely 50um fiber. I now officially have infinity+1 projects so it'll be a while before I have a chance to try and form a monolayer of my own. My offer stands to send an envelope of 50um fiber strands to anyone who wants to give it a shot and is willing to share their results. The paper notes that the construction method is similar to that for imaging fiber bundles. Perhaps some research into that will prove interesting.

PM sent

Optical grade UV cured adhesive would have a known property. Since they are assembling bundle optics as a corporation, they would have some "nice" polymer materials with a controlled low index for this. They would have drawn the fibers themselves from a high index glass.

I called Machida US.. They have 50 and 25 micron in stock.... 650$ Each... I do not remember them being "THAT" expensive, long ago, but they were expensive. So only Brad could afford them.. :-( Let me know when you want their phone number Brad.....

Steve

[Junktronix]

Packet of fibers on it's way.

I recall the real 50um Machida gratings were $495. But that was back when I got my Machado for 'only' $70. I think they're about double that now. Does Machida spec the power handling capacity of their gratings?

[mixedgas]

I spoke with a older lady, She was only interested in quoting a price, making a sale, and getting on with her life. I was supposed to speak to the expert, but I got the functionary instead... So I don't know on the power level, but I think it has to it to be immense.. After all, these were regularly hit by 17 Watts of White light or 25 watts of Argon from a 171... In a beam far tighter then nearly anything that exists today in show world.

Steve