Help!!! AC-coupling for Laser Driver

Discussion in 'General Electronics Chat' started by Rattapoom Tidprom, Jul 14, 2015.

  1. Rattapoom Tidprom

    Thread Starter New Member

    Jul 14, 2015
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    I'm starting to understand laser driver (especially Maxim laser driver). I'm having a hard time to understand why we have IL = IBIAS + IMOD/2 when optical high output and IL=IBIAS-IMOD/2 when optical low output. (IBIAS and IMOD are constant current sources). I've also attached the article that you can find the basic details about interfacing with Maxim laser driver.

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  2. #12

    Expert

    Nov 30, 2010
    17,887
    9,294
    The bottom, right drawing seems to illustrate why AC coupling causes a +/- effect with the modulating signal. I think you merely overlooked the idea of AC coupling making the modulating signal cause both greater and lesser excursions of the bias current across time.
     
  3. Bordodynov

    Well-Known Member

    May 20, 2015
    1,098
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    hope you will help my calculation. I found that the average current through the inductor is equal to half. See my chart.

    Laser_AC_Mod.png
     
  4. Rattapoom Tidprom

    Thread Starter New Member

    Jul 14, 2015
    3
    0
    @Bordodynov - How can get plight from LTSpice? Can you take the snap shot? I'm trying to learning from simulator also.
     
  5. Rattapoom Tidprom

    Thread Starter New Member

    Jul 14, 2015
    3
    0
    Is it additional library for laser diode?
     
  6. @Bordodynov Could you show me step-by-step for your simulator? i need to learning for usage this simulator. thank you.
     
  7. Bordodynov

    Well-Known Member

    May 20, 2015
    1,098
    333
    Last edited: Jul 16, 2015
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