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Thread: lasing threshold and standby current

  1. #1
    Join Date
    Dec 2009
    Location
    Laurel, MD
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    298

    Default lasing threshold and standby current

    So I'm trying to integrate this diode into a projector I've had for a while. I have a flexmod driver but it's giving me one small issue. I've seen it all over here that the lasing threshold of these is 200mA, but I'm still getting light out of mine at as low as 3mA. When I set the bias to 2.5mA I cannot set the gain higher than 4mA. I'm trying to hook this up to a TTL blanking circuit and the diode isn't blanking, it just gets dimmer. I'm sure I'm missing something obvious but I'd really appreciate any guidance I can get here.

    Thanks.

  2. #2
    Join Date
    Jan 2009
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    1,622

    Default

    Every single direct-diode analog laser that I've ever seen still emits some light at standby.. The best you can hope for is that it's not enough light to contaminate the imagery you're projecting.

  3. #3
    Join Date
    Dec 2009
    Location
    Laurel, MD
    Posts
    298

    Default

    ahhhhh, so there's no hope of getting the beam to completely attenuate without killing power to the driver? That's a shame, it's a great looking beam. If I can't attenuate it then I'll have to figure something else out. Thanks.

  4. #4
    Join Date
    Oct 2006
    Location
    Cleveland, Ohio
    Posts
    2,333

    Default

    What does the output of your ttl driver look like on a multimeter? It's possible that you need a pull up resistor on it if it is an open drain configuration. At 2mA bias, the diode should be pretty darn dim. At that point, with the pull up resistor, you should still be able then to turn on modulation current to full with your ttl controller.

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