PHR-803T batch testing.. Windowless 803Ts?

[Zom-B]

Yes.

I already forgot I typed that and in the mean time I learned the "cavity" is not gas but solid crystal. Other than that, I didn't know it was a 'stimuating emission LED' as opposed to pumped.

I know the theory of stimulated emission and different types of waveguides, though I don't know which waveguide is used in the LD.

 

[Zom-B]

My 201mw died. Runtime was around 18:30 minutes, after the 60 minutes duty-testing. It was run at a mere 222mA. The testing was done at 240mA.


The current, 222mA, was in the middle of the third tier, that is, after the second kink. Although this is just the first one, I'm already thinking that running them in the third tier will never lead to long lasting diodes.


Another one of my unconfirmed theories is that the diode is more likely to die when driven at a current which is inside one of the knees, as opposed to a current between two knees. If this is true, this could explain the stories of all those of diodes dying at a young age, who's owners have set the current of without the new knowledge from the past few weeks. If false, it would simply mean that even at a current in the middle of the second tier, lifetime is not long.

In other words, I will now set all my experimental diodes (three left) inside the second tier, and see if I can confirm or falsify this theory.

 

[Zom-B]

I finally managed to get a mode shift on video. I managed because the mode shift is extreme, compared to other diodes. Normally it's much less notable.

Diode curve:

Video:

[media]http://www.youtube.com/v/qsbWE1gYrGw[/media]

 

[Zom-B]

Here's some videos of mode shifting and wavelength shifting of another violet PHR-803T diode.

I used diode #24, and to remind you, here's the graph again:

Mode shifting vid:
[media]http://www.youtube.com/watch?v=EGdUY84EVfE[/media]

In the next two videos the wavelength is plotted on a wall. It is the second order beam from a CD-R diffraction grating. I'll describe what I see as it is not that clear in either video.
- In the first part, up to the first kink, the wavelength increases
- Inside the first kink, the spectral width of the line seems even narrower
- Between the first and second (small) kink, there seems to be a band of wavelengths present, at about a magnitude weaker than the bright line. This band moves with the line, but the right bound (lower bound on wavelength) is even lower than the initial wavelength.
- Just after the second kink I can see spectral pollution all around the central line. The most striking is a weaker line left of the line (higher wavelength) at a distance from the centrel line of about the same as the total distance traveled by the central line.

Wavelength shifting of diode #V24V
[media]http://www.youtube.com/watch?v=QAp4gLzUApI[/media]

Another video of the same diode diode
[media]http://www.youtube.com/watch?v=yckWsDp8S0I[/media]

Final finding:
#24 has a lower wavelength than #27 when both at a weak power, but with #27 at a low power and #24 at 150mW the wavelengths are equal.