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Thread: using LSR (laser speckle reducer) with a pico projector, ideas about design need

  1. #21
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    ... I think, it's sort of a compromize - smallest source vs. highest energy throughput.

    The size of the source between 0.05mm to 0.2mm will slightly affect refocussing or divergence ... but with bigger core size the received/transmitted energy percentage should be much better too ...

    Viktor

  2. #22
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    Thanks again. I have a LPM , I should be able to measure the differences and decide.

    Last questions and then I'll be off dissecting the UO Smart Beam.
    Do you polish your custom cut fibers after cleaving or is the fracture smooth enough by itself for this?

    I guess I'll start with a 10mm long fiber and go from there if the length isn't enough for reducing the speckle.
    I'm surprised I haven't seen this used in other video or laser projectors before. Seems simpler than dichroic combining or knife edging same color beams for increasing brightness.

  3. #23
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    ... I' using cleaving only - it's good enough to survive more than 30Watts @975nm out of the 105µm fiber

    First, when using super sharp blades and manual cleaving, it sometimes needed several attempts, until it was perfect -- then got a proffessional cleaver with a diamond blade, what was much better.

    But, with this cheapish chinese cleavers with a round cutting disk, it's even better and much shorter waste length

    Viktor

  4. #24
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    I see. Thank you.
    So what tools would you use to accurately position a fiber and secure it in place? The fiber-lauch? Would you have something on the tip of the fiber from both sides?

  5. #25
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    Hi guys. Where should I get or from what can I harvest 50 and 100 micron fibers?

  6. #26
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    ... 105 micron fibers are used to "pigtail" IR pumping diodes for fiberlasers.

    Have a lot of them (and loose fibers too) salvaged from broken IPG fiber lasers.

    50 micron fibers are used with lower power IR diodes -- have one with max. 1 Watt power (my diodes with 105µm fiber emit max. 5, 9, 25 and 30 Watts) ...

    Viktor

  7. #27
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    I guess what I'm trying to ask is where can I source fibers or what can I use? I don't really have any laser modules to salvage from myself.
    There are some telecommunication cables that have 50 or 125 micron fibers inside. https://www.alibaba.com/trade/search...+optical+fiber

  8. #28
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    ... where are you located?

    Viktor

  9. #29
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    Quote Originally Posted by VDX View Post
    ... where are you located?
    Corsica.

    ...I thought an ordinary singlemode fiber is used. Is there something special about laser fibers?

  10. #30
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    ... the fibers for the pumping diodes are "normal" glass fibers with a core diameter and cladding around.

    Resonator fibers in the fiber-lasers are more special - there are some with pretty thin cores (e.g. 5 microns), others can have special structures (varying densities or air-gaps) inside or around the core to optimize the resonator modes and laser beam quality ...

    Viktor

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