how far can you push a red diode?

[ashenfang]

I have an OPEN can red diode from a DVD R burner 16x i believe. How far can you push these (mA wise) ? I guess the better question is how far can you push them AND have the diode last?

 

[Blord]

Is that a Long Open Can or Short Open Can diode ?

Here you find the information about both diodes, Red laser - Laser Wiki

 

[anselm]

The other I had a diode like that, apparently a long open can.
It was lasing happily at ~350ma, then it went POP at ~420ma....
Mine might have been damaged by handling it though, I'm not sure.

Here's some pictures:
http://laserpointerforums.com/f50/open-can-alright-but-long-short-58962.html

 

[ashenfang]

From the link you posted looks like a short can but not 100% positive.

 

[LaZeRz]

probably 420ma if u want good life

EDIT: around 320ma (sorry was thinking of a LOC 20x lpc-815 Diode)

 

[planters]

I have been running some cooling tests of the LPC-815 diodes in a cooled heat sink. Run at 0C I have run 3 separate diodes for short periods ie. 15 min. at 700 ma and 500mw raw out (without a lens) with out any apparent damage. Further, I have run one diode now for approx. 18 hr at 550 ma without any change in it's 350 mw output. Of note, one diode was pushed to destruction and between 700ma and 800ma (when it went LED) there was no increase in output rather just a wavelength shift from 662nm to 669nm. Hope this helps.

 

[lazeerer]

Guys he said he Extracted it out of a 16x burner he believes ansd says it looks like a Short Open Can. Running that diode at 420mA will be a certain death.

If it is a 16x diode Keep it under 350mA. I would set it to 330mA.

 

[planters]

Your right about 16X and those seem like reasonable numbers.

 

[lazeerer]

http://laserpointerforums.com/f50/red-laser-diode-roundup-36202.html:whistle:

 

[planters]

As a follow up re. my previous post the LOC-815 diode survived for 21.5 hr at 550ma and 350 mw output (through a lens) and then went LED. Based on the statement by ANSELM I began another test at 420ma and -1.5C and so far so good at 12 hr. Interestingly, the power only drooped to 290mw at this lower current. As a point of reference the Aixiz lens used cuts out 30% of the raw output of the diode.

 

[planters]

I have completed two more runs and at the same temperature the next diode lasted 36.5 hr at 420 ma with 270 mw (thru the same Aixiz lens) and the other diode lasted for almost the exact same duration of 37.0 hr with 390 ma and 255mw. Am now running a third diode at 350 ma and 230 mw and at 15 hr so far so good.

 

[anselm]

This brave man is sacrificing diodes to gather data for our hobby!
I laud you, good man!
+1

 

[Illuminum3415]

Like LEDs, thermal bottlenecks exist inside the emitter housing, the effects of the bottleneck is minimized when operating within current specs. However, it would mean that even if the housing is cooled by liquid nitrogen it is still theoretically possible to burn out a diode through over-current and consequential overheat.

 

[planters]

You're right about that. However, based on my testing of these diodes with the Aixiz modules, I have found that even with modest wavelength shifts on the order of 4nm to 5nm they have gone LED after a few tens of hours. This implies that there is some accumulating facet/coating damage at the higher ma (and higher mw) settings that occurs at junction temperatures ( based on wavelength) that are no higher than those that occur when the diodes are operated within spec. and only passively cooled. Furthermore, my original goal in testing these diodes was to try to fill a gap in the red wavelength when constructing large multi-diode projectors. The alternative to the LOC-815 diodes are very expensive 200mw 642 nm diodes that look to be about $70 each. The LOC-815 diodes that I've tested operate at 657 when passively cooled on a large lab style heat sink and cost about $10 each. When cooled to -30C with a single stage TEC (in an Aixiz module and like you point out this is important) the LOC-815 puts out at least 260mw at 649 nm. But, when mounted in a custom (not fancy) copper heat sink the wavelength drops to 647nm. A second stage TEC is still not complicated and at -50C 645nm is reasonable. I'll be testing this next and let you know.

 

[Illuminum3415]

hmm...sounds like the current sensitivity operates non-linearly if it begins to shift wavelengths close to the upper tolerance limit of specs.
Are all red lasers producing the light directly? It sounds like there's something else going on in there.

 

[planters]

I'm sorry I don't understand. Yes these red lasers are producing light directly as opposed to DPSS lasers for example. And the wavelength shift is continuous and pretty linear at approx. 0.2nm/C.