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Size measurements of emission face of various diodes, mostly single mode.

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This is a sharp 505nm single mode laser diode.
I measured the emission surface area, and 3d scanned the emission surface depth relative to the top face of the metal can. I plan to make each post I make in this thread another laser diode with the same measurements taken. The tool Im using to do this is our RnD companies Keyence VHX-7100, and it takes me an hour or so per diode I scan, but whenever the machine and myself get a free hour I will do the next wavelength of single mode diode. I have around 10 unique wavelengths of single mode diode to image and measure before I go to multi-modes. Happy to measure diodes that get mailed to me.
 

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RedCowboy

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I have also looked at the facet and it appears the P/N junctions output is but a small slit near the middle of the facet, look closely at the center of the facet on the right in my pic below........granted the entire substrate stack glows blindingly bright, but the beam emission point is much smaller than the width and breath of the facet, with the right amount of light and at the right angle you should be able to see it with a USB microscope. Note the 2nd pic is at just above threshold current.

1kxnubm06a-jpg.67404

0921-6-jpg.62412

SemiconductorLasers_JDSU_Figure1.jpg
 
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RedCowboy

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The front and back of the substrate stack has a thin coating of reflective material much like a gas laser uses a back mirror and output mirror often called an output coupler, a partially reflective mirror or mirror with an output region in the center, the material science amazes me, seems like it would burn up being so tiny given the energy density.

You can just make out the laser diodes pins above the waveguide in my pic which is looking down at the end of the substrate stack and the tiny black spot is the emission point, just the glare from it is overdriving my little USB cameras CCD, it's just a 20 dollar ebay toy but works pretty well.
nubm06raw4-jpg.67405


Here's a little interesting reading about how small the active regions actually are and another about how the reflective coatings are deposited.



 
Joined
Jun 19, 2010
Messages
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With your guidance, I took new measurements with the diodes outputting.

many diodes 505nm lit 20x small.JPG
505nm face outputting small.JPG

505nm output area measured small.JPG

The 2.1um x 8.2um face area appeared to be the source of the 505nm emissions.

Here is a 940nm SM diode which appears to have a larger emission area. Not certain my widths are correct here, it was difficult to capture the bounds clearly on the most inside emission area.
940nm SM face output area measured small.JPG
 
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Messages
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This is a 670nm single mode at lase threshold. 670nm SM last threshold face measured small.JPG

808nm SM face lasing small.JPG
That above diode is a 808nm single mode diode, and it has a relatively large emission area (its also possible Im being tricked by local reflections and the source point is smaller).

This one is a 450nm single mode diode, that somehow got its lens shattered. Im sure it was my fault, but not sure what I did to cause it.

450nm single mode broken lens small.JPG
 

RedCowboy

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Great pics.
Pop the can off that single mode 450, it looks like the can window shattered from getting hot and exposed to moisture in the air.
 
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Great pics.
Pop the can off that single mode 450, it looks like the can window shattered from getting hot and exposed to moisture in the air.
Thanks! It was difficult to get them, and I know my emmisions point sizes are still larger than reality, and I think the glass lens in front could be causing some optical artifacts. Do you have a good process to get the glass lens off without damaging the diode?
 

RedCowboy

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The 9mm cans pry off with a screwdriver if in a module or you can crack them loose in a vise with a pair of channel locks but the smaller ones I secure the diode in a vise and work on the can/backing union with a razor knife.

If there sealed with indium you could use a heat gun which I use for extracting diodes from the blocks but never have bothered with heating the cans, mostly I just remove the GBall cans which are easy, there's also a tool which is just a razor blade deal.
 




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