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Thread: Looking for a multimode fiber combiner

  1. #1
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    Default Looking for a multimode fiber combiner

    Does anyone know where I might find 800um multimode fiber combiners to combine the power from multiple FAP800 diodes?

    SMA 905 ideally.

    Alternatively, I am open to buying an 808nm 500+ watt fiber coupled laser in its entirety but this seems to be a specialty item I am having trouble sourcing. Lots of 1080 but no 808.

  2. #2
    Join Date
    Oct 2021
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    I have many IR passing fiber splitter cables which combine 6 to 8 fibers into a single fiber, however if you require a good beam profile and low insertion loss (so it doesn't melt), the part you're looking for can't be built into and adapter without the adapter knowing your beam profiles and mode distribution. It would look more like an optics bench with beam expanders and gratings and collimators to do what you're asking at high power.

    I think your lowest cost and effort is going to look like a single output fiber coupled module. If you can tolerated a 220micron diameter fiber tip and 915nm, this unit would work.

    https://www.alibaba.com/product-deta...5a237552Pj6tql

  3. #3
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    ... what is your intended application?

    I have several 975nm-diodes mit 200W or 270W output power, "internal" fibercoupler into a 0,2mm fiber -- I'm using them by removing the fibercoupler and focussing the parallel beam externally ...

    Viktor
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  4. #4
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    Here's a listing of a single FAP800 split 12 ways, that's a lot of splitting, but I wonder, since the FAP is likely bad if you might be able to cut the fiber off of the FAP and find a way to use it, if not too many ports? svcstore: https://www.ebay.com/itm/114577390611

    Beware of this ebay seller svcstore (above ebay link), they have a lot of broken burned out bad shit they list, even using nice Kapton tape to make a FAP800 look new as if they are just old stock, most of the time they are not NOS and instead burned out. Also, they pack like shyt, I stopped buying from them after too many damaged items due to their idiotic-stupid careless packing, I gave them chance after chance to pack correctly, seemed they just took offense to it after I complained the last four packages I received from them were not packed well, I mean BAD, just putting parts inside a box to bang around the whole way to me, smashing optics and breaking off parts. What svcstore is, is a hazardous materials recycling company hauling off trash from Coherent Inc. and then selling it. That's why they treat the parts like trash, THEY ARE TRASH. I am wondering if they don't have an agreement not to resell these materials which they are paid to dispose of, but someone at Coherent is getting a kick back, so they look the other way?

    This seller on ebay (not to be confused with the above seller) had some FAP800 splitters listed in the past, he has a lot of stuff he doesn't list, maybe ask him:

    https://www.ebay.com/itm/264196863174
    Last edited by Laser57; 11-02-2021 at 03:42.
    Avatar is camera photo flash reflection. Doggy was found as a six week old puppy near dieing of thirst in the desert here in Qatar, she's a Saluki mix. I'm from Ohio, just working here.

  5. #5
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    ... this "splitted" FAP diodes are not really usefull -- better look for this type with a "bundled" output - https://www.ebay.com/itm/15436472527...75.c101224.m-1

    I have some of such bundled FAP's - there are mostly 19 emitters, each coupled into a fiber -- so the 40Watt-type should have something like 2 Watt per fiber ... then either a "bundled" FAP or mybe even better one of the IPG diodes with multiple 9Watt or 10Watt emitters, coupled into a single 105µm fiber!

    Attached a comparison of a 3x9W-into 105µm and a bundled 19x FAP...

    Viktor

    *** EDIT *** -- a side note - the small laserdiode below the 19xFAP is a single 9W-diode, coupled into a 105µm-fiber ... the same 9W-emitter, as the three in the 3x9W-type.

    When focussing the diodes, I'm receiving a spot of roughly 0,1mm with the 9W and 25W (3x9W) diodes, compared to rougly 0,6mm spot size with the 19xFAP with the same optics setup ...
    Attached Thumbnails Attached Thumbnails 25W-Diode_3.jpg  

    25W-Coherent.jpg  

    Last edited by VDX; 11-02-2021 at 04:27.
    Aufruf zum Projekt "Müll-freie Meere" - https://reprap.org/forum/list.php?426
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  6. #6
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    Since the last post shows the 19 emitter fiber coupled arrangement inside the Coherent Inc. infrared wavelength FAP, I have a photo to share with you which was taken using a cheap digital camera with the IR filter removed showing a collimated beam output into the night sky I took a few years ago, at the far end of the beam you can see the energy from the individual emitters.

    These modules have terrible divergence using a 12.7 mm diameter collimation lens, however, a FAP800 laser module was never intended to be used for a free space output like this. I only did this once outside and only long enough to snap a few photo's. I searched the net for a long time trying to find a night time sky shot of one of these modules using an IR sensitive camera, none exist I could find, so had to do so myself. Before someone says it, I will, it's a potentially bonehead dangerous move to use one of these like this, thus why I couldn't find one. Thankfully I am unware of anyone putting one of these into a jumbo sized pointer for such use, mine was strapped to a BIG passive five pound finned aluminum heat sink using a EnerSys Cyclon 25 amp hour 2 volt lead acid battery attached to it with tape for a short duration supply. Very ghetto, but functional.

    I used this battery without a constant current regulator: 0820-0004 Enersys 2V 25.0Ah BC Cyclon (batterystore.com) - I could do so without current runaway because the 40 watt FAP couldn't run long enough to get too hot using this battery, the voltage kept dropping too fast. With the Cyclon 25 ampere hour battery I had 10-15 minutes runtime for close to full output power, but the output power will keep dropping the entire time as the battery drains. Of course, the heat sink must be large enough to do this without a current regulator or the diode will get too hot reducing runtime life, or perhaps outright fail the first time you try to use it that way as it pulls far too much current. With my 40W FAP and large heatsink the battery would drain too fast to allow the diode to overheat enough to be a problem, at least, for the limited time I used it that way testing my setup inside my apartment several times into a laser power meter, running the battery down quite a lot during several 20 minute tests, recharging each time which took awhile. Your performance may vary! Just making it clear I tried this several times without a driver and the diode survived.

    Photo: Beam shot deep into the night sky, many hundreds of feet, possibly thousands of feet long before fading into the distance.
    Attached Thumbnails Attached Thumbnails InkedInkedFAP800_LI.jpg  

    Last edited by Laser57; 11-04-2021 at 00:50.
    Avatar is camera photo flash reflection. Doggy was found as a six week old puppy near dieing of thirst in the desert here in Qatar, she's a Saluki mix. I'm from Ohio, just working here.

  7. #7
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    Viktor,

    In the top picture of your post you show 3 of the 9W IR diodes being combined into a single beam before going into the fiber launch. I have a question about that layout: Are the three diodes at the top each offset slightly in the vertical axis, so that the beams can be knife-edged and stacked on top of one another by the bounce mirrors at the bottom? So you would end up with a beam profile that looks something like this: " = "?

    Also, if that is the case, then what does the beam look like when it comes out of the far end of the fiber? Does it still maintain the triple-stack of individual beams, or do the beams get smeared together by the multiple internal reflections of the fiber?

    Adam

  8. #8
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    ... I'm using the laser diodes mainly for "material processing" like engraving, soldering, brazing, welding and cutting ... or "enhance" the welding capabilities to SLS and 3D-printing of different materials (powder or wire), which can be melted/fused with the specific waverlengths and powers.

    Actualy I have single modules with 2W/3.5W/6W/40W@450nm, 5W/20W@652nm, 25W/300W@808nm, 5W/9W/25W/30W/200W/270W@975nm and several CW fiberlasers with 50W/85W/130W@1070nm ... and pulsed with 16W/30W averaged or some ten Kilowatts peak power @1064nm ... and a "Head" to combine up to 12 of the focussing heads onto a single spot.

    AFAIK, when combining different wawelengths into the same spot, then the material absorption rates rises noticeable so more effective welding/sintering

    Viktor
    Last edited by VDX; 11-02-2021 at 05:50.
    Aufruf zum Projekt "Müll-freie Meere" - https://reprap.org/forum/list.php?426
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