Fun With A 200-kW Fiber Laser

We’ve all heard the “Do not stare into laser with remaining eye” joke. It’s funny because it’s true, as pretty much any laser a hobbyist can easily come by can cause permanent damage to eyes unless the proper precautions are taken. But a fiber laser with 200kW peak power is in another hazard class entirely.

Granted, outsized power ratings like this are a bit misleading, based as they are on femtosecond-long pulses. And to be sure, the fiber laser that [Marco Reps] tears down in the video below was as harmless as a kitten when he got it, thanks to its output optics having been unceremoniously shorn from the amplifier by its former owner. Reattaching the output and splicing the fiber would be necessary to get the laser lasing again, but [Marco] had other priorities in mind. He wanted to understand the operation of a fiber laser, but the tangle of fibers on two separate levels inside the chassis was somewhat inscrutable. The coils of fiber wrapped around the aluminum drums inside the chassis turned out to be the amplifier; fed by a semiconductor seed laser, the light pulse travels through the ytterbium-doped fiber of the two-stage amplifier, which is the active gain medium where stimulated emission, and therefore amplification, occurs.

With a little reverse engineering and the help of an online manual, he was able to understand the laser’s operation. A laser company helped him splice the optics back together – seeing the splicing rig in action is worth the price of admission alone – and the unit seems to be in more or less working order at this point. Normally the most powerful laser we see around here are the CO2 lasers in those cheap Chinese laser cutters, so we’re looking forward to learning more about fiber lasers.

19 thoughts on “Fun With A 200-kW Fiber Laser

  1. “Granted, outsized power ratings like this are a bit misleading, based as they are on femtosecond-long pulses.”

    I figured that had to be peak pulse power; a laser that’s “only” 2 kW continuous power output is well past “Do not look into laser beam with remaining eye” jokes and gets into “Do not touch laser beam with remaining fingers” turf. Were there any notes on the laser’s continuous power output?

      1. Trust me when I tell you that the box with the laser source in a commercial 4kW fiber laser is no bigger then 1m cubed.
        Granted, its chiller and it’s heat exchanger are about the size of 2 fridges side by side, but the (very) expensive box of laser magic is disapointingly small :D

        A resonator and it’s power supply for a 4.5kW CO2 laser are waaay bigger.

    1. There are some “commercial” videos, granted, but most of the stuff is high quality content with particularly dry humour I personally like very much. Just check out the CNC videos for example or the other laser videos. Heck, even the teardowns. There is a lot of good content there IMO.

  2. For what it’s worth these 1064nm lasers are way more dangerous than a CO2 in that CO2 is ~10600 and is absorbed by water. So you can burn the surface of your eyeball but that can be transplanted. A 1064nm laser will blast the rods and comes of your eye. So game over with no continues.

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