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NEW LOC Laser diode review.






Without touching the die with calipers, The die appears 1.58 mm long with 2 fine connecting wires.

HMike
 
Very strange diode, does look like one that could work very well in a driverless build :)
 
Asherz --- That's a quandry --- Driverless build may push this over the hump and all you get is heat and a little power output. Like a clown on the big ball in a circuis, you need to ride the peak which is ~ 400 mA. Kind of a balancing act.

I still haven't tested another diode from the lot yet.

HMike
 
Are the new LOC's supposed to be better than the old ones? Because I run mine at 420 mA and it outputs 252 mW with an aixiz glass lens.
 
Silver --
Compare the data on yours to my data and they likely appear close -- This was represented to Greg as the NEW red diode. It is different!

HMike
 
I'm not saying they are not different :) Are they better ? I was just wondering because as I said mine outputs 250 mw
 
Silvershot ---
Exactly what we are saying. My equipment reads a peak of 240 mW at 400 mA. Almost the same as yours. However - beyond that, this diode goes into a different world. The foldback is something I have never observed in a LD.

HMike

Tonight, I get 212 mW at 400 mA. This is less than the 240 mW I got last night but remember, I pushed this diode over 1 AMP twice last night. It still lases!

HMike
 
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Hemlock_Mike said:
Silvershot ---
Exactly what we are saying. My equipment reads a peak of 240 mW at 400 mA. Almost the same as yours. However - beyond that, this diode goes into a different world. The foldback is something I have never observed in a LD.

HMike
Click to expand...

Oh ok. I am sorry. It's 3:33 am here and am very bored :P
I'll read the 1st post once more ^^:angel:

EDIT: I understand now lol. ^^
 
TheMonk said:
SOC (short open can) you get this in 6x blu-ray sleds or 16x DVD Burners.;)
Click to expand...
But the "can" is LONG, die is short :p unlike the SOC which has a short can.

Edit: Also, the GGW 6x has a LCC (long closed can) :p
 
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Interesting!

COD is normally caused by excessive laser power causing damage to the output facet.

The output facet acts like the laser equivalent of an RF impedance-matching device, which because it is not 100% efficient, can be damaged or destroyed by excessive output levels (COD). As a result, LD manufacturers spend a lot of effort coming-up with special coatings & other tricks, in order to increase the safe laser power levels that the output facet can handle.

This LD seems to have a built-in safety feature, when the LD gets past a certain power level, it seems to become less efficient, converting most of the power to waste heat!

But by reducing the efficiency, it also reduces the output power, preventing COD! :cool:

Kinda like the old Pentium 4's, that "down-shifted" when they got too hot, in order to avoid self-destructing.

I imagine if you put enough power into it, you could eventually fry the leads or crack the die. But this shows you where the limiting factor on output power is on these things (at least for these reds) - it's not heat, it's the output facet!

This could make LDs a LOT more reliable!

Unfortunately, it also places the equivalent of a "speed limiter" on the LD, thus limiting what we can do with them too. :cryyy:
 
So when a laser diode is "LED'd," it's because the facet isn't reflecting the emitted light back into the diode so that it can gain?
 
Rather than simply smoke Diode 1, I installed Diode 2 into a same housing.

Amazing! --- This diode is almost the same as diode 1. About 10 mW higher at 400 mA but still exhibits the unusual foldback on the power curve. I was actually hoping to see 400 mW single mode RED........
Dromidary Diodes -- Single Hump ??

Could someone have designed into these diodes a self protection configuration? If so -Why?

HMike
 
These are odd readings indeed - you would expect the power to go up with current until the diodes simply fail.

Are you certain that your measurements are accurate, even when compensating for the increase in tempeature and hence wavelength?
 
BShanahan14rulz said:
So when a laser diode is "LED'd," it's because the facet isn't reflecting the emitted light back into the diode so that it can gain?
Click to expand...

Yes, if it gets damaged from excessive power so that it can't reflect the light back properly, it can turn an LD into an LED.

Hemlock_Mike said:
Could someone have designed into these diodes a self protection configuration? If so -Why?
Click to expand...

See my prior post above.

I am curious how they are accomplishing this. Perhaps some thermally-sensitive compound in the crystal to interfere with the process when things get too hot?

This would also explain the substantially reduced output power you are seeing at higher current levels. It's not just LIMITING the output power, it is actually pushing it down farther at higher currents!

So perhaps the hotter the LD gets, the more this kicks-in to reduce lasing efficiency, the lower the output power goes? :thinking:
 
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