IR pumping diode replacement

[Laser201698]

Hi!
I built a laser pointer using DX "200mw" green laser module.
It was a good cheap laser and i paid it only 20 bucks.
Anyway, after trying to increase the current of the IR pumping diode,
i finally destroyed it :cryyy:

Since i am a machinist and i can deal with no problem with small precision parts, i have a question for you:
Is it possible to replace the pumping diode with a new one?
Will it work a 500mw 5,6 mm 808 nm IR pumping diode?
I know that the IR diode will cost like a new DX laser module, but i am pretty sad to put my module in the trash :cryyy:

 

[diachi]

Hi!
I built a laser pointer using DX "200mw" green laser module.
It was a good cheap laser and i paid it only 20 bucks.
Anyway, after trying to increase the current of the IR pumping diode,
i finally destroyed it :cryyy:

Since i am a machinist and i can deal with no problem with small precision parts, i have a question for you:
Is it possible to replace the pumping diode with a new one?
Will it work a 500mw 5,6 mm 808 nm IR pumping diode?
I know that the IR diode will cost like a new DX laser module, but i am pretty sad to put my module in the trash :cryyy:

Assuming the crystals sustained no damage from the increased pump power, then yes, it's possible to replace it. Is it worth it? Not so much... Wouldn't expect 200mW out with a 500mW pump either - best case is probably somewhere around ~150mW.

 

[Deleted member 16589]

Asuming the diode was not an open can and was not butt pumping it (Diode emitter up against crystal) Then it may work but don't expect anything near 200mW. I have bought these in the past for my 50mW module and they were at least at the time right on spec. 5 6mm 500mW 808nm Infrared IR Laser Diode specially for Producing Green Lasers | eBay

Make sure u have goggles for 808 and 1064 as well as green as you will have to fiddle with it. It is not always as simple as just a quick swap.
Honestly other than a fun project I have to agree with Diachi its not worth it.

 

[Laser201698]

""Asuming the diode was not an open can""
Why it can't be done if it's an open can?

 

[diachi]

""Asuming the diode was not an open can""
Why it can't be done if it's an open can?

What he's saying is that if it was an open can you're going to have a hard time with a closed can diode. The die won't be able to get close enough to the crystal with a closed can - the can/window will get in the way. May still work if it fits but you won't get the same performance as you would with the open can.

On second thought - it may well be open can - many of these are. Good point lazerman! :beer:

 

[Laser201698]

Honestly i think that my module is weaker than 200mw (nominal power). The driving current of the diode is 250mA so i think we are dealing with a 300mw pumping diode. A 500mw would absorb 700mA as i seen on some datasheets... My laser diode seems to be an open can, so, since with a ""not open can"" diode i will lose some power i think a 500mw replacement diode would be pretty good
What do you think?

 

[diachi]

Honestly i think that my module is weaker than 200mw (nominal power). The driving current of the diode is 250mA so i think we are dealing with a 300mw pumping diode. A 500mw would absorb 700mA as i seen on some datasheets... My laser diode seems to be an open can, so, since with a ""not open can"" diode i will lose some power i think a 500mw replacement diode would be pretty good
What do you think?

Yeah ... not a 200mW module if it's only supplying 250mA to the diode. That's 200-300mW pump power - enough for at best 100mW green output.

That's assuming the closed can diode even fits - the can may get in the way so much that it doesn't even fit - you'd be better replacing it with an open can diode if it's open can just now. I'd go for a 300mW open can 808nm driven at 250mA... Too much power and you risk cracking or otherwise damaging the crystals.

As I said ... not really worth fixing anyway. Especially once you account for your time, cost of additional equipment (Electronics equipment and safety equipment).

 

[paul1598419]

I think expecting an output of 100 mW from a 200 mW to 300 mW pump source is very optimistic. These are usually confined to about 20% to 25%.

 

[Deleted member 16589]

What he's saying is that if it was an open can you're going to have a hard time with a closed can diode. The die won't be able to get close enough to the crystal with a closed can - the can/window will get in the way. May still work if it fits but you won't get the same performance as you would with the open can.

On second thought - it may well be open can - many of these are. Good point lazerman! :beer:

Thanks I was too slow to answer for them.

and no problem. I rebuild dead green modules for fun every now and then its not hard if you know what your doing.
The ones i prefer are the ones where the diode is closed can held in by retaining ring and optically corrected.

The trick is when you swap the diode the new output is almost never clean. You usually get a trail of multiple dots or splotches. You then have to rotate and wiggle the diode and optics around until you get a TEM00 dot.
Sometime but very rare you will get one that no matter the rotation of the diode you get perfect tem00. I have only ever seen 2 and I smoked the crystal in one getting cocky wanting more power.

 

[Laser201698]

Do you know where can i find an open can diode? I usually buy diodes on ebay, but it looks hard to find an open can laser diode.

Anyway, the diode is placed far from the crystal and it seems like there are no lens between them. I am not sure about that, i still haven't removed the diode, but maybe we have enough room to place a closed can one.

Don't misunderstand me, i agree with you, an open can diode is better, but if it's difficult to find one, it's the only way to try to fix my module

 

[Deleted member 16589]

Do you know where can i find an open can diode? I usually buy diodes on ebay, but it looks hard to find an open can laser diode.

Anyway, the diode is placed far from the crystal and it seems like there are no lens between them. I am not sure about that, i still haven't removed the diode, but maybe we have enough room to place a closed can one.

Don't misunderstand me, i agree with you, an open can diode is better, but if it's difficult to find one, it's the only way to try to fix my module

Diode is far from crystal with no optics Weird got any pics of it.
we cant really determine what diode you need without pics

 

[Laser201698]

I took some photos


I was not able to extract the diode, I tried pulling it from the back, soldering a sort of "puller" to the pins of the diode, but I ripped the pins :tired:
I tried this way because i preferred not to move the glued KTP Crystal in front of the diode.... :cryyy:
Can you explain me how to extract the diode without damaging the Crystal?

 

[diachi]

I took some photos
View attachment 52599
View attachment 52600
I was not able to extract the diode, I tried pulling it from the back, soldering a sort of "puller" to the pins of the diode, but I ripped the pins :tired:
I tried this way because i preferred not to move the glued KTP Crystal in front of the diode.... :cryyy:
Can you explain me how to extract the diode without damaging the Crystal?

Looks like it's press fit - you'd need to push it out from the front.

 

[Laser201698]

Do i need to remove the glued KTP crystal in front of the diode?
I guess that re-sticking the crystal in front of it with a correct alignment shouldn't be easy

 

[diachi]

Do i need to remove the glued KTP crystal in front of the diode?
I guess that re-sticking the crystal in front of it with a correct alignment shouldn't be easy

You'd remove the whole brass crystal mount - usually just glued onto the brass diode mount.

 

[Laser201698]

You'd remove the whole brass crystal mount - usually just glued onto the brass diode mount.

Yeah....but... is it difficult to re-glue in position?