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Active surface of a laser diode?

Discussion in 'Electronic Repair' started by N_Cook, Apr 1, 2013.

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  1. N_Cook

    N_Cook Guest

    For self-education I decided to take apart a presumably defunct DVD laser
    unit to see the internal layout of splitters etc and what the laser diode
    looks like. Googling in images I only find graphics or external views,
    anyone know of a WWW view through the window of some good laser diodes ?.
    Looking via x30 at what I assume to be the active surface is a uniform grey
    colour and uniform crystalline appearance rectangular face (ie no obvious
    hot spot/s) like a finer grained version of a fractured surface of cast
    aluminium or monkey metal.
    Is this the infamous Catastrophic Optical Damage ?
    This one has a marking of RH on the body.
     
  2. N_Cook

    N_Cook Guest

  3. Den 01-04-2013 13:56, N_Cook skrev:
    How about the small 'rod' that the 4 bonding wires from the right pin
    goes on top of?
     
  4. I think the laser diode is the long gold bar with four wires going to
    it.
    I'm not sure what the silver cube next to it is.. a temerature
    sensor?

    The whole thing is on some substrate.. maybe Alumina or Silicon??

    The emitting area of a laser diode is really tiny.

    George H.
     
  5. N_Cook

    N_Cook Guest

    Smaller than the resolution of that photo or the small blackish rectangle on
    the end of the "bar" that ends flush with the granular surface, on a line
    between the centres of the end faces of the conductor pins.
    Dimensions of that rectangle about one of those wires diameter x about 4
    wire diameters
     
  6. Sjouke Burry

    Sjouke Burry Guest

    If it is a visible light laser diode, just use a lens to produce
    an image of the chip on your wall.
    That is safe to look at, and shows the light distribution.
     
  7. N_Cook

    N_Cook Guest


    I went the "unsafe " route and put 2.5V and 560R over the 1.6V DVM diode
    test junction ( 1.3V of the other pair of pins of this recordable DVD
    laser). The dim and dull-red light came from the junction between the grainy
    block surface and the pillar . In my one the end of the pillar is a
    "polished" surface with no metalisation over it unlike the one in that pic.
     
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