Open Can Diode Lifetime

[DZ]

Ok, the stress test on the open can diode has finished. The diode failed after 167 hours. It was originally set to 252mW and measured several times over the past week. The measurements vary from 251mW to 260mW. It is currently putting out less than 1mW, almost like it failed to back reflection, which didn't happen. So, an interesting result.

[MechEng3]

Temperature of said test subject? Just wondering about this aspect....

[DZ]

The diode was in a maxy module, clamped to a rather large heat sink with force air cooling. I let it run for about an hour at the start of the test without air cooling and it was rather warm. After adding the air cooling, it was barely above room temperature.

[drlava]

thanks for the report. I run mine at 200mW and haven't blown one yet (knock on silicon)
Not knowing much about the internals of a maxy, was the diode press-fit into an aluminum heatsink, I.E. was the thermal interface resistance low between the diode and the module?

[tocket]

Sounds very reasonable. Definitely along the lines of my own findings:
http://www.photonlexicon.com/forums/...ead.php?t=6055

This is something to keep in mind for all of us who build our own red modules. While the diodes themselves are cheap, you don't want it to fail during a show, which isn't very unlikely when you overdrive these DVD burner diodes.

[drlava]

The good news is that if you use 2 with a PBS, all red is not lost .

[DZ]

I think around 200mW is a much safer range for these. When I get time, I'll throw in another diode and let it run at 220mW and see how long it lasts.

drlava, it is pressed into a module of some kind, it's not aixiz though. It is a brass fitting, someone linked to a website for buying them, but can't remember where. May have been deal extreme.

[drlava]

You might be talking about these:
http://www.alltronics.com/cgi-bin/it...dule-US-Lasers
http://www.us-lasers.com/lasdiohs.htm

The ones that I sampled the diode just fit in a chamber and there was a brass lip to fold over to hold it in. If yours had a press fit, that is better.

[FourDee]

So 200mW = ???mA for these? (300mA? or less )

[mixedgas]

I am the linkee of the fitting

Meredith Instruments sells the 5.6 mm to big can adapter.
www.mi-lasers.com/

I've used them, no problems.
Steve