Fast laser switching causing damage to diode?

[ben_makes]

Hi, I'm trying to build a driver circuit that will allow me to rapidly switch on and off a laser using an Arduino. However, this is not simply for brightness control via PWM. I need it to be able to turn on for specific intervals of time, then off for another specific interval of time. This needs to be very accurate. The on/off times are as low as 1 microsecond.

So for example lets say: ON for 5µs, OFF for 3µs, ON for 7µs, OFF for 9µs, ON for 2µs......etc.

I already successfully built a constant current power supply using an LM317 and successfully powered a 532nm (DPSS) 200mW green laser with it. No issues with that...

I then added a mosfet (P30N60LE) to the output of that and tried to use the arduino as the control signal. The laser came on for a split second and then burned out.
Why did this happen? Do these diodes not like being switched on and off rapidly? Was the issue current overshoot?

I was using a 532nm because I wanted the highest brightness for the power rating, but I could use another type if need be. Any suggestions on what might be causing the diodes to burn up?

Thanks.

 

[WizardG]

532nm is DPSS. I'm guessing the driver in the module didn't like the rapid-fire power cycling. Try with a direct diode laser. Be mindful that your circuitry doesn't generate current/voltage spikes when switching the laser on. You might want to try a gated shunt-regulator topology for clean output.

Diode lasers have very low rise and fall times. They can be switched on and off VERY rapidly. The laser in a blu-ray writer is switched at many MHz in use. Lasers used for fiber optic data communication are switched in the GHz.

 

[paul1598419]

Hi, Ben. Like WizardG said direct diode lasers are very capable of very fast switching and if you want a green laser I would look at the many 520nm options available to you. You can get up to 1300 mW in output power with one of these diodes, but there are also many that will do less and give you a nice output at a reasonable price. Good luck.

 

[ben_makes]

Thank you both for the info, I am going to get some different diodes and make some changes to the circuit - hopefully I can get everything working this time.

 

[atomd]

And if you insist on switching DPSS laser I suggest either thermally stabilizing crystal or externally gating laser