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Re-terminating fibre optic cable.

rhd

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Is this doable?

I have a cable that cannot be detached at the source end, but the output end is unterminated. I can't seem to even get a clean break on the fibre, which I gather is a precursor to even thinking about termination.

Any thoughts?
 

crazyspaz

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Doable, yes. But, if you dont have the specific tools for the job, it will be a royal PITA (getting a clean, even surface on it). I would contact Dr. G, he would probably be your best bet. I am assuming this is for your fiber coupled diode you snagged?
 

rhd

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Doable, yes. But, if you dont have the specific tools for the job, it will be a royal PITA (getting a clean, even surface on it). I would contact Dr. G, he would probably be your best bet. I am assuming this is for your fiber coupled diode you snagged?
Yep it is. Not sure who Dr. G is though. The problem, is that if the cut isn't perfect, with 12W travelling through the fibre, any imperfection causes the tip of the fibre to burst into flames.

I managed to get a fairly clean cut using a traditional razor blade, believe it or not. I used a sort of "cut and snap" approach. It seems to be workable now. Of course I still need to figure out how to terminate this into some sort of connector, ideally without having to drop money on crimpers (that are probably 5x more expensive than they should be, on account of their narrow application).

Fibre seems to make this "linear array" look single mode. Is that normal?

http://laserpointerforums.com/attachment.php?attachmentid=46683&stc=1&d=1418398096
 

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crazyspaz

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Dr. G= Sam Goldwasser, of Sam's laser FAQ.
Is the whole thing rated at 12W, or is it rated 12W out of the fiber?
Have you checked thorlabs? They have everything you need, from cleaving tools to connectors. Not terribly expensive, either. You will get a single mode-ish looking output out of the fiber. The point of fiber coupling those arrays is to get a usable output from them. A 40W IR flashlight doesn't do anyone any good :)
 

rhd

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Dr. G= Sam Goldwasser, of Sam's laser FAQ.
Is the whole thing rated at 12W, or is it rated 12W out of the fiber?
Have you checked thorlabs? They have everything you need, from cleaving tools to connectors. Not terribly expensive, either. You will get a single mode-ish looking output out of the fiber. The point of fiber coupling those arrays is to get a usable output from them. A 40W IR flashlight doesn't do anyone any good :)
Regardless of what it's rated (which I'm not clear on), I get 10+ Watts out of the fibre on my Ophir (which now maxes out at 10W), so I'm fine with that.

I've never known thorlabs not to be expensive. Frankly, there's a matter of perspective here, and I recognize that fibre coupled diodes are in the realm where that relativity gradient gets pushed upwards. But I don't have the budget (or desire) to go spend $50 on fibre splicing / terminating equipment.

My ultimate goal is to modify the laser engraver I purchased to use the fibre output, so I'd like to not spend a ton of money terminating the fibre. IE, I would like to spend almost nothing :)

I'm not demanding, am I? lol ;)
 

DashApple

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I had to re do my 1.3W diodes that had damaged fibres .

I used a craft knife to introduce a defect and then pulled on the fibre before and after the defect till it broke in two , it gave a good results .

I did try " bend and snap " but gave lesser results .
 
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What is a diameter of the fiber?

Try to fix a fiber at ~10 cm at the end you want to cleave/cut. A tape can be sufficient to hold. Then pull that end and make a slight cut though don't crush through. If done properly it cleaves well though not perfect.

As for termination. Do you have a connector? Could you use this Thorlabs - BFTU Universal Bare Fiber Terminator or an analog.

Otherwise post pics.
 

rhd

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What is a diameter of the fiber?

Try to fix a fiber at ~10 cm at the end you want to cleave/cut. A tape can be sufficient to hold. Then pull that end and make a slight cut though don't crush through. If done properly it cleaves well though not perfect.

As for termination. Do you have a connector? Could you use this Thorlabs - BFTU Universal Bare Fiber Terminator or an analog.

Otherwise post pics.
What do you want to see pics of?

At this stage, it's just a 3mm bare fibre.

No, can't use the Thor labs part. It costs $75. My budget is more like 5 ;)

I bought one of these:
ST Multimode Metal Housing 3 0 MM Fiber Optic Connector | eBay

Any reason I can't add this to the fibre?
 

Sigurthr

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Depending on the fiber material and application some fibers are actually cleaved and then polished with special compounds to achieve a particular surface finish.

I've only had to terminate data level FO systems where it wasn't critical, but I'd always used a new razor blade while putting mild tension on the fiber cable to ensure a clean cut and not a crushing cut.
 

ultimatekaiser

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Yeah it's usually polished at the end of a very special machine. If you want to terminate it in your house you can buy a special cutter for it depending on the type of fiber, but they're not cheap. If you know any computer technicians, they might loan you one. I think Thorlabs also sells them but I'd have to check. I find thorlabs is usually the best place to get tools for relatively inexpensive way compared to a lot of other lab sellers (Newport I'm talking to you) how thick of a fiber we talking about?

Edit: ah missed the size bit. 3mm is pretty big indeed. But anyway yes you can put one of those tips on the end probably, but you'll still end up needing the cutters to get full transmission. Good fiber is expensive. Just the way it is :(
 
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rhd

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Yeah it's usually polished at the end of a very special machine. If you want to terminate it in your house you can buy a special cutter for it depending on the type of fiber, but they're not cheap. If you know any computer technicians, they might loan you one. I think Thorlabs also sells them but I'd have to check. I find thorlabs is usually the best place to get tools for relatively inexpensive way compared to a lot of other lab sellers (Newport I'm talking to you) how thick of a fiber we talking about?

Edit: ah missed the size bit. 3mm is pretty big indeed. But anyway yes you can put one of those tips on the end probably, but you'll still end up needing the cutters to get full transmission. Good fiber is expensive. Just the way it is :(
I have had fairly good luck using a razor, but it's not perfect, and every once in a while the end of the fibre bursts into flames (so I guess that's far from perfect).

I ordered some 5,000 grit sandpaper. I know that's a long shot. But bottom line here is that it's not worth buying a tool to repair the fibre that costs more than the diode, so I need to find a way to do this on the cheap. I actually have faith that I'll figure something out. I'm so close.
 

Gadget

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RHD, try hitting up a cabling contractor in your area. You should be able to get one termination for really cheap...especially if you take the fiber to them.

-G
 

ultimatekaiser

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Yeah borrowing is an option. Or try a fine polish on a thick paper. Ceramic polish is super fine. Around half a micron. Might be able to use that
 

ultimatekaiser

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Okay. What do you mean by thick paper?
similar to the kind of stuff sandpaper comes on, or if you have a fine grit stone you could use that for polishing. I actually have a waterstone that is 120000 grit ceramic. you could use the slurry from something similar to polish it I imagine. perhaps pour some jeweler's rouge or something similar onto a sandpaper back somehow and use it to grind down the tip? I assume it'd be hard enough to polish glass? A high pressure very sharp cutting tool might work too.
 
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What do you want to see pics of?

At this stage, it's just a 3mm bare fibre.

No, can't use the Thor labs part. It costs $75. My budget is more like 5 ;)

I bought one of these:
ST Multimode Metal Housing 3 0 MM Fiber Optic Connector | eBay

Any reason I can't add this to the fibre?
Pics - to understand what you do.

The datasheet (if it is for your model) says a connector is SMA 905. You bought ST. That is not a problem. What about the hole size? 3 mm is for boot. Does your fiber pass through the hole when cleaved and stripped?

As I understand you are doing some burning ("modify the laser engraver "). Can it be that your fiber end gets contaminated by fumes and then starts a fire? BTW, what burns?
 




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