A peculiar Russian pulsed power laser diode, teardown

• A peculiar Russian pulsed power laser diode, teardown
  Posted by Bendba on 29 Jun, 2017 01:57
• Hi,
  
  Yesterday, I received two 30W pulsed laser diodes I bought on ebay from Ukraine. I was really looking forward to experimenting with them.
  
  When I went to do some measurements on them, it appeared that the diodes were both dead shorts. Didn't look good.
  
  After a couple of emails exchanged with the seller to organize return and replacement, he informed me that he found that diode mentioned on a Russian forum and that there is actually a current transformer integrated in the casing of the diode.
  
  I couldn't help it, I had to see it for myself. So I took it apart and took a heap of photo so I could share with other people who would be intrigued by it too.
  
  This is the diode out of the box:
  
  
  
  
  
  
  
  
  
  
  
  First took to cover off on the diode side. You can see the diode sitting in an isolated seat and pressed on the other side by a connection to the case.
  
  
  
  
  
  
  
  Here, you can see the substrate of the diode itself.
  
  
  
  And the spring loaded contact on the other side, with a lead connected to the case for better conduction.
  
  
  
  
  
  I managed to pull the diode out of the casing without too much damage.
  
  
  
  
  
  And you can indeed see some wire wound down there.
  
  
  
  
  
  Some more chopping. That thing is built to resist the impact of a US nuke. Not the casing being tinned copper but the cap was steel. I'm wondering what technique was used to weld them. (I'm guessing friction/spin welding)
  
  
  
  And finally the transformer revealed itself.
  
  
  
  In that gel like podding, is the primary winding, double up 10 turns around a ferrite ring core. But where is the secondary?
  
  
  
  Of course, the casing, made out of one solid lump of copper is the single turn secondary.
  
  
  
  
  
  
  
  And that's what I'm left with.
  
  
  
  Time to make a little drawing and diagram of the "diode"
  
  
  
  
  
  
  
  And guess what, the diode itself still lights up. It's got a strange ~8v voltage drop. That's pulling 500mA and getting hot but not very bright though. Wonder what the luminous efficiency is. (Assume around 10% at best. 8V drop. This one was tested at 133W of light output at the factory. That's pulsing around a KW or over 125A. No wonder you can only pulse it for 100ns)
  
  
• #1 Reply
  Posted by fourtytwo42 on 29 Jun, 2017 06:01
• Might have been good to try translate the data sheet..... Beware looking at it, maybe a UV diode so although you think it's not bright it could easily burn your eyes.
• #2 Reply
  Posted by Bendba on 29 Jun, 2017 06:08
• I'm working on the translation, it'll be up in a couple of days.
  
  No way I'm looking at it, not taking the risk.
  The camera I've taken the photos with is fairly sensitive to ir, that glow is not even as bright as what a dvd laser diode is to the camera.
• #3 Reply
  Posted by with on 29 Jun, 2017 06:35
• This diode is infrared (900nm) , and was used to illuminate the target in the night vision sight.
  It was designed to work only in pulse mode, so no DC current applying. Duration of current pulses = 100ns, and working freq = 500Hz, rms Power = 15mW and pulse Power = 300W , equvalent imput resistance of diode is 60 Ohm, type of structure GaAs. Do not exceed the applying pulse parameters Ton = 100ns, tr/tf 10ns (+\-).
  That's all.
• #4 Reply
  Posted by with on 29 Jun, 2017 06:41
• Quote from: blueskull on 29 Jun, 2017 06:37

  Quote from: with on 29 Jun, 2017 06:35

  This diode is ultraviolet (900nm)
  

  
  You meant IR?
  

  Yes .. sorry , my missed.