how do I identify a LD from a burner?

[ashenfang]

I just pulled apart a DVD burner from a desktop and pulled the laser diode out. The label on the burner says H-L data storage, Hitachi-LG Storage Inc. Model GH41N. It doesn't look like the normal 5.6mm can. How do you identify how much current it can take?

 

[Grix]

Power it up at ~10 mA and slowly turn the current higher. Note when it starts to lase. The treshold current is usually a good indicator of the diode's rated power. If the treshold current is ~70mA for example, the diode is probably good for 150-250mW. But make sure the diode is actually red, not infrared used on CD-burners/readers.

 

[ashenfang]

thanks for the info...now remind me, on a LM317 driver, what resistor value would I want to use to achieve 150mw?

 

[Grix]

We don't know the efficiency of this laser diode, so that is hard to say.

But for current, ohm of resistance = 1.25/desired current in amps

 

[LtKernelPanic]

I would almost bet that's the IR diode. Every one I've pulled has had a plastic lens on the front of the heatsink like that where the red didn't. I've only pulled them out of pioneer drives fwiw. You'll know if it's the red or not when you power it up. If all you see is a dim cherry red than that's the IR which are not good diodes to mess with until you're comfortable building normal lasers.

 

[Scottyzedinosaur]

Holy giant pictures, batman!
But yes, that is most likely an IR diode

 

[Coherent Light]

Please DO NOT LOOK INTO THE DIODE!!!! It may look dim but it'll be putting out more than 5mW I can bet you...Be CAREFUL!!

 

[LtKernelPanic]

CL is 100% correct about the danger of IR diodes and I should have said the same thing. When you test the diodes point it away from you. If it's the red you'll know it for sure. When I test diodes harvested from sleds If I didn't get a bright red light from it I put a piece of paper in front of it and look at it from an angle to avoid IR exposure. Every time I've done this I could see the tell tale sign dim cherry red color of an IR diode on the paper.

 

[benmwv]

Another good way to identify wether it's ir without risking exposure is to pull out your phone camera (or any camera I guess) amd look at it through that. If it's red the light will be red through the camera but if it's ir it will be a pinkish color.