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I am currently reviewing pulsed laser diodes from suppliers. The specifications are somewhat unique, so there doesn't seem to be many suppliers that offer what I'm looking for. I require an IR wavelength pulsed laser diode with a frequency of 3 kHz and a pulse width of 10 ns. I found a Chinese supplier on Alibaba that was selling IR pulsed laser diodes with a frequency of 1 kHz and a pulse width of 150 ns. The supplier told me that the frequency and working pulse width are adjustable, and that I can adjust the frequency to 3 kHz and the working pulse width to 10 ns myself. Is such a thing possible (I'm assuming by the design of our laser driver)? Does making such adjustments negatively impact the laser diode in any way (for instance, by lowering the lifetime)? If making such adjustments does negatively impact the diode lifetime, then can such a thing be mitigated (perhaps, for instance, by ensuring proper cooling)?

P.S. I'm not looking to buy anything now, but rather see what's commercially available to guide my design.

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  • \$\begingroup\$ If you exceed the device's detailed ratings, that will shorten the device's life. So, the device datasheet is your friend. Thus, if it is sold without an adequately detailed datasheet, you have no friend. \$\endgroup\$
    – user16324
    Jul 13, 2021 at 11:32

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Is such a thing possible (I'm assuming by the design of our laser driver)?

Yes. As 10 ns is not really that fast for a laser diode, this doesn't sound surprising – any 5€ SFP fiber optic transceiver can do that!

3 kHz is like, seriously, slow. Any microcontroller can trigger something at 3 kHz.

Does making such adjustments negatively impact the laser diode in any way (for instance, by lowering the lifetime)?

I don't see how adjusting the pulse repetition rate (please don't call it frequency, that's very ambiguous) has downsides, as long as you keep it low enough for the diode to not overheat due to being on most of the time. And that's very far from the case here.

Regarding pulse duration: Well, as said, 10 ns isn't really fast for a modern laser. Still, you'll need a fast driver. When you know your pulse length, you can optimize the drive for least overshoot, low laser chirp etc. But you don't seem to know what you really need in that, so I guess that means you don't care about such parameters.

In that case, no real downside.

P.S. I'm not looking to buy anything now, but rather see what's commercially available to guide my design.

Write some specs! I'm serious, your last two questions suggest that you're not really deep into what a pulsed laser is; which is OK, one doesn't have to be an expert in everything. But now you're asking questions that make more or less sense because nobody but you can tell what properties of the device "pulsed laser" are important to the application "The Pointer's project". You need to nail down the properties you need, or you can't move ahead in your design.

So, I'd recommend asking another question where you describe exactly what you need that laser for – and what the critical aspects of its usage are. You could then ask for which properties in a pulsed laser you should be looking for. Then, you'd have something to go and ask suppliers about, rather than just taking two not-very-challenging numbers and asking them to make an offer.

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    \$\begingroup\$ My apologies for the ambiguous terminology; I'm still learning the basics. I think what I'm referring to is en.wikipedia.org/wiki/Pulse_repetition_frequency , right? Or am I mistaken? \$\endgroup\$ Jul 13, 2021 at 8:42
  • \$\begingroup\$ yup, that's right. \$\endgroup\$ Jul 13, 2021 at 8:43
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    \$\begingroup\$ Thank you very much for the helpful answer. Yes, I still have much work to do, so I will undoubtedly be asking more questions in the future as I continue my studies. \$\endgroup\$ Jul 13, 2021 at 8:53
  • \$\begingroup\$ @ThePointer that'd be great! \$\endgroup\$ Jul 13, 2021 at 8:58

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