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Fast (ns) rise/fall light source

Discussion in 'Electronic Design' started by Spehro Pefhany, Feb 5, 2011.

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  1. Looking for a light source (50-100mW or more output would be good),
    somewhere around 550-1000nm that is _fast_, maybe 1-2ns rise/fall
    time. I'd like to keep it under $100 one-off; it's just for a test..
    found a OTDR laser module for somewhat more than I want to spend (it
    will need a driver too) and there is info on RCLEDs and other exotic
    stuff, but very little in the way of inexpensive bare laser diodes or
    LEDs with decent specs. Most IR LEDs, if they are spec'd at all look
    to be in the hundreds of ns. Most visible ones are not spec'd at all.

    Any inexpensive tricks here?


    Best regards,
    Spehro Pefhany
     
  2. Ah, I think I've found the solution .. inexpensive VCSEL laser diodes
    with 50ps rise/fall.. only a few mW output power, but with a laser it
    should be usable. Everybody and his dog seems to make reasonably fast
    laser driver chips.


    Best regards,
    Spehro Pefhany
     
  3. Yet for the same wavelength and similar Vf I can find LEDs with
    ~1us/100ns/10ns/1ns specs. Three orders of magnitude. Very strange.
    Nice product. Thanks for the offer, I may take you up on it.
    Clean, no spinning logos or other junk.. very good.


    Best regards,
    Spehro Pefhany
     
  4. Ecnerwal

    Ecnerwal Guest

    How does $5 strike you? You would have to go dig the laser out of it,
    but that's about what I've paid for used SFPs on eb*y, which have a
    diode and a laser in them....you can get new ones for $50 or less (or
    you can pay several hundred for certain brands, but you don't need to.)

    The really high power ones will be longer wavelengths than you want, but
    the wavelength you want is also available. Get gigabit SFPs, they all
    have diode lasers or VCSELs.
     
  5. Ecnerwal

    Ecnerwal Guest

    Curiosity got the better of me. At the moment, $3.99 will get you an
    850nm 2GB SFP at the large watery "auction" site.

    To get 2GB data rates, it _has_ to be turning on/off faster than 1 nS

    If you're willing to rip it open, I doubt you can get cheaper (depending
    what you are doing, you may not even need to rip - just sort through the
    pinout to make it behave as an assembled unit.)
     
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