LASER Diode

[zahid61]

Hi all,
I need a 50 nano second LASER pulse to send for 4 meters. What kind of driver is best?
Thanks

 

[IRstuff]

How about a trifle bit more information? Like what kind of laser diode? What's the drive current?

TTFN

FAQ731-376

 

[zahid61]

Thanks IRstuff for the reply. The pulse current is 5A and repitition rate is 100 microseconds. Diode is 3W pulse laser diode. I would appreciate if some design material is suggested in this regard.
Thanks again dear.
Zahid

 

[IRstuff]

Why not just buy one? Doesn't the LD manufacturer have recommendation?

This company's drivers we've used a LONG time ago:

http://www.directedenergy.com/pdf/pco-7810_manual.pdf

http://www.directedenergy.com/directedenergy/products/LaserDiodeDrivers/laser.htm

TTFN

FAQ731-376

 

[zahid61]

Thanks dear, in fact I have space limitations so was interested to build my own.

 

[IRstuff]

DEI's sister division makes the MOSFETs used in their diode drivers:

http://www.ixysrf.com/pdf/switch_mode/appnotes/5mosfet_driver_theory_and_applications.pdf

TTFN

FAQ731-376

 

[zahid61]

This document will be of great help. Thank you dear.

 

[IRstuff]

I would dig around for any documents related to their and others' diode drivers. Building something that runs a 50 ns pulse is nontrivial. DEI has another document on their site that describes the series inductance problem. If that's not minimized, you'll need a wonking large drive voltage to get the current through your device.

TTFN

FAQ731-376

 

[zahid61]

I have tried avalanche transistor earlier but high voltage is again another constraint. I am given only 40 vdc. Even while trying the avalanche transistor at 150vdc the lazing I was having was not really loveable? May be the inductance problem you talked now?

 

[IRstuff]

I would suggest that you look at something like:

http://www.directedenergy.com/directedenergy/pdf/products/Manuals/LaserDiodeDrivers/mnpco-7120.pdf

If not buying outright, perhaps duplicating it with slightly less capacity, since it's designed for 50 A. Either that, or have them do it for you. If you do it yourself, you'll probably wind up iterating at least once, so it might be cheaper overall to have them design a customized version.

The linked datasheet shows some nice photos of the driver board. Note that you can probably eliminate the heat spreader, since your current draw is on the low end of the device's range.



TTFN

FAQ731-376

 

[zahid61]

Thank you dear indeed for this quick chat we had on the forum. I shall work again on my assignment.
sincerely,
Zahid