Laser diode vs. Laser Module? What is the difference?

Discussion in 'General Electronics Chat' started by Nathaniel Zhu, Nov 10, 2015.

  1. Nathaniel Zhu

    Thread Starter New Member

    Oct 16, 2015
    I'm having trouble finding a clear explaination of what the difference is.

    The only physical difference I can see is that the laser module is much bigger than the laser diode and that the laser diode is a part of the module (since by definition, module implies many parts).

    But what extra stuff is in the module and how does that affect the function?
    Can a laser diode by itself provide the same function and the laser module?

    In other words, does the module affect the light output in any way?
  2. MikeML

    AAC Fanatic!

    Oct 2, 2009
    Laser modules include a separate photo detector device which is used to "measure" the light output and provide feedback to the driver. If you try to run a Laser module without closing the feedback loop, you will smoke it...

    Laser diodes are low-power, and their dissipation can be sufficiently controlled just by picking a series resistor or limiting current some other way.

    The driver used with high-power Laser Modules dynamically modulates the emitter current to keep it just at the peak light output and prevents runaway and destruction of the module...
  3. RichardO

    Well-Known Member

    May 4, 2013
    Also, I believe that some modules have optics to make the Laser diode's natural oval beam shape more circular.
  4. NathanielZhu

    Active Member

    Dec 5, 2011
    I asked a colleague and he said that in addition the laser module also has:
    -Build in power regulation
    -Can come in higher power varieties than laser diode
    -Has a higher selection of wavelengths than diodes
    -Super precise. He says we modules in our flow cytomters are $10K ea! (daaaaaammmmn!)
    -I think he also described the module laser as being composed of something different than just sticking a laser diode in a large metal can with some fancy circuits
    -Laser diode is cheaper

    I think he said a lot of other stuff but that's all I can remember off the top of my head

    I forgot to ask him if laser diodes also containing that focusing crystal.
    I so, is it that thin/rather reflective piece of glass in the opening of the laser? I'd imagine that a crystal has to be long and thick (no pun intended) like the ruby used to the red laser.