Hi,
iv been looking a a modulated laser diode driver but I cant seem to find the right one, I need to modulate a standard red diode laser with a 16mhz signal. If anyone has done something like this before could you please let me know, any help is appreciated.

Thanks

 

just drive it at 16Mhz.

 

I'll need to design a driver for my laser diode with feed back, I have found this circuit but I dont know how to analyse it:

http://www.fiber-optics.info/articles/laser-diode.htm

its figure 7(a). The laser diode i'm using is 20mA rated. The feedback part is giving me the most difficulty. Also is there any other way that I can test it without putting the laser in, chances are I'll end up killing it. Thanks again.

 

It's always a good idea to have a few spares on hand when you're prototyping.

What is the intedended use?

__________________
Bill
Smart Kits build Smart People
http://www.blueroomelectronics.com

 

I'll need to design a driver for my laser diode with feed back, I have found this circuit but I dont know how to analyse it:

In the circuit Q1 and the emitter resistor R2 form a constant current circuit, whose current level is set the voltage applied from U1 via R1.

The Vref sets the Vs output of the OPA. When the Laser is energised the D2 diode detects the emitted light. The strength of the light detected is amplified by U1, as the strength of the emitted light detected rises, the output of U1 falls so that constant current is reduced to ensure the laser current stays within it current limits.

A quick test would be insert a 50mA current meter in place of the laser diode.
Adjust the Vref pot so that the meter current is about 20mA.
Of course without optical feedback the output of U1 will be constant.

When you reconnect the laser diode any current due to the laser light falling on the D2 diode will drive the U1 output in a direction that will reduce the current below 20mA.

Does this help?

__________________
Eric
"Good enough is Perfect"

PIC tutorials:
Gramo's: www.digital-diy.net/
Bill's: www.blueroomelectronics.com/

 

Yes it does, thank you. I have the skeleton of it setup and will try testing tomorrow.

 

Unfortunately I have a small budget for this project, and have bought some expensive components for other parts of it. Its gonna be part of a laser range finder.