laser overdriven?

[vincenthooi]

what happens to a laser diode when overdriven without a heat sink? will it go off instantly or will it become slightly dimmer over time?

 

[vincenthooi]

i wanted to know because my laser diode extracted from pioneed 115bk running at 550ma doesnt seem as bright as the first time i run it.
and can anyone give information on wavelengths of the following diodes?

LG GH22NP20 22X
Pioneer 115bk
pioneer 213ls

 

[vincenthooi]

rather than a 250mw+ laser diode, it feels like 80mw-130mw. :'(

 

[GooeyGus]

thats because you're running it at 550mA

thats over 100mA more than what people usually recommend for those diodes (I'm assuming its a long-die open can)

 

[Bionic-Badger]

At that current, I'd be surprised if you'd see any lasing at all before it died.

 

[Switch]

Wow, it must've been a nice 300+ mW before it suffered damage.

 

[IgorT]

550mA?!? What kind of heatsinking did you use?

People usually use peltiers at those power levels!


I'm making a tiny portable TEC cooled open can (with a heatsink on the hot side and a fan blowing on it), but it never even crossed my mind to go over 470mA. I want it to live.

Open cans are expensive here..

 

[vincenthooi]

i am NOT using any heatsink except for the bare aixiz tube. i thought it would kill the diode outright.
but it is still very bright. so... does this means it is damaged?

 

[vincenthooi]

:-[hehe whoops my silly mistake- i drained my batteries. a quick change and its done. ;D now its back to its original brightness. :-[

will put in heatsink when i find a proper casing. ;DLOL

 

[artix]

:-[hehe whoops my silly mistake- i drained my batteries. a quick change and its done. ;D now its back to its original brightness. :-[

will put in heatsink when i find a proper casing. ;DLOL

you can get a meredith collimator with the 9 mm adapter and a heatsink! you need the adapter because you have a 5.6 mm diode and the collimators fit the 9mm diodes...

 

[IgorT]

i am NOT using any heatsink except for the bare aixiz tube. i thought it would kill the diode outright.
but it is still very bright. so... does this means it is damaged?

I'm sorry, but that's just... :

An open can dissipates a lot of heat! In your case, almost 1.5W... A 16x diode dissipates only 0.7W which is little in comparison, but it still gets hot in only an AixiZ module. An AixiZ module is a heatsink by itself, but it can not handle that much for more than half a minute.

You're torturing the diode for nothing. The heat causes the power to drop, and you're not really getting much more power from all that extra current.
You would get more power and longer diode life at 420mA, if you had a good heatsink.

With the setup you have now, your power may start high, but it starts dropping very fast. Simply glueing the AixiZ to a big chunk of aluminum would be better than that.

 

[styropyro]

and you're not really getting much more power from all that extra current.

Shouldn't he get a decent amount more power at that current? Gazoo got over 400mW out of an open can at 570mA. Gazoo was using a Merideth glass lens though.

 

[IgorT]

Well yeah, but Gazoo was using a peltier! Heat reduces the power. You can end up using a higher current and getting less power, simply because of heat. The power would still start higher, yes, but it would drop very fast if the heatsink is nothing more than an AixiZ module.

I had an open can in an AixiZ module alone, at 420mA, and the power was nothing special compared to a 16x, simply because it heated up too fast. That's why i'm giving it a tiny peltier cooling system now (15x15mm Peltier, finned aluminum heatsink, pager motor blowing air over the fins with a small helicopter tail rotor). That and a multilayer custom lens... Should be interesting. Need to buy another open can, to put it in a Meredith module for comparison.

 

[vincenthooi]

yeah i took the hint and bought some copper heatsinks out for it.
still, can any one tell me what wavelengths are the following diodes?

pioneer 213ls
pioneer 115d/115bk
LG-GH22NP20

any help is appreciated.. thanks

 

[IgorT]

All DVD diodes are 655nm..

As they heat up, more like 660nm. Or in your case, 670nm.. (kidding) But they are referred to as 650nm.


The drives you listed should contain the same open cans as the Sony NEC 719x drive (long chip open can)..
Not 100% sure about all of them. If they don't, it could be a powerful but useless flat square diode...

If you get a long chip open can, it's the same in all drives.. There are no differences. Just go with the cheapest drive, that you know for sure, that it contains the long chip open can. Usually that's the NEC 719x.. Sony NEC 720x contains the square diode, as do all Samsung drives for example.

 

[artix]

Well yeah, but Gazoo was using a peltier! Heat reduces the power. You can end up using a higher current and getting less power, simply because of heat. The power would still start higher, yes, but it would drop very fast if the heatsink is nothing more than an AixiZ module.

I had an open can in an AixiZ module alone, at 420mA, and the power was nothing special compared to a 16x, simply because it heated up too fast. That's why i'm giving it a tiny peltier cooling system now (15x15mm Peltier, finned aluminum heatsink, pager motor blowing air over the fins with a small helicopter tail rotor). That and a multilayer custom lens... Should be interesting. Need to buy another open can, to put it in a Meredith module for comparison.

can a senkat diode work well at 400ma with a meredith collimator and heat sink without dying?