Thanks for reading. I was hoping someone could help me with the electronics of my project. So I am trying to drive a L980P200 - 980 nm, 200 mW, Ø5.6 mm, A Pin Code, Laser Diode. Link to spec sheet from Thorlabs. I have been browsing forever for a laser diode driver and I ended up ordering the LD3000R - Laser Diode Driver, 2.5 A Constant Current. Use this link here from Thorlabs.

I don't know if this will work. I need this laser driver to be able to modulate current at 10khz to compliment my photodetector which I will be using a lock-in amplifier with. I ended up buying Thorlab's T1G - Laser Diode Bias-T modulator (I can't post more than 2 links).

Could anyone tell me if this will work? In addition could someone tell me if I am able to drive this laser diode? The driver is rated higher than the laser diode laser= 1.5V, 200mW output power and 300-400mA driving current, while the driver=2.5 A, 7.7 V.

  • \$\begingroup\$ Use double line-break to create paragraphs. "thorlab" should probably be capitalised if it's a brand name. Separate the questions out at the end so that it's very clear what you're asking. +1 for proper linking on first post. Welcome to EE.SE. \$\endgroup\$
    – Transistor
    Jul 4, 2016 at 23:01
  • \$\begingroup\$ @transistor. I made a few corrections for the OP-this time. \$\endgroup\$
    – user105652
    Jul 4, 2016 at 23:58

1 Answer 1


This may work.. On the diode datasheet, you can see that the laser power graph only goes up to 280mA, but your constant current source is going to provide 2500mA. I would suggest you find a 250mA constant current source to correctly use this diode.

Edit 9/27: the link to the old sheet for the power supply is broke, and I was redirected to the new datasheet. anything below is strictly the new sheet.

There appears to be a 5V analog control on the module that I did not see before. Using this, It would be possible to modulate the laser diode's supply using modulation, such as a 5V PWM signal, or even a voltage divider. If you decide to go the voltage divider route, then I would use values of 1k and 9k.

  • \$\begingroup\$ one of my goals though was to modulate the current from the driver so as long as the biasT modulator would output current in the safe operating range I would be ok. Is this not true? \$\endgroup\$
    – Hunter Lin
    Jul 5, 2016 at 19:43
  • \$\begingroup\$ @HunterLin I would not try modulating the current on this device, it seems to already modulate the output. \$\endgroup\$
    – user86234
    Jul 5, 2016 at 20:17

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