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I have a 250mW 660nm cni module and I would like to cool to bring down the wavelength to enhance its visibility. I have a bunch of sealed housings ,TECs, drivers. So that's not a problem. My question is, is there a limit to which these modules can be cooled? Or what do your think is a reasonable temperature ?
There's some points to take care with :
- no condensation should appears on the diodes (you can calculate the condensation point, it depends on ambiant temp, humidity, and the temp you want to reach, or something like that)
- the diode's efficiency increase when temp decrease, so if you're already driving your diodes hard, you can exceed the max allowed power...
Now I don't know how the condensation can be dangerous, if your modules are entirely sealed and waterproof, and if the diode are closed can.
I remember once on my dual maxyz, I had a failure on my home-made TEC, and all the max current passed to the TEC, resulting of some condensation on the diodes. I don't know how long I runned them in that condition, but they are still alive and outputting a little less than 500mW after optics :D
On short wavelength diodes ie 635 or hard driven diodes, cooling can blow the mirror faucets off the diode face from the increase in power density in the lasers. Back in the late 90s I tried that, and Bob Ash at NML tried that. It gets real easy to kill the diode for just a shift of a few nanometers,
I'm not saying dont try, I'm saying be forwarned that you need to back off the current and then do a long test run with modulation, ie several days or weeks.
Steve