B&W Tek BWB-10-OEM - 473nm 10mW

There is a TEC on the diode mount and the entire crystal assembly is contained in an airtight box that is secured to the TEC underneath it. There's no FAC, there's no need, as they use a set of corrective prisms and lenses. And remember, there's an APC, so 3W is not 'insane' for 'only 10mW' only 10mW was needed, so the APC holds it steady at 10mW, which is why removing the APC gives 25-35mW of output power.


Edit: Although I do believe the diode is less than 5W.

Prototype said:

There is a TEC on the diode mount and the entire crystal assembly is contained in an airtight box that is secured to the TEC underneath it. There's no FAC, there's no need, as they use a set of corrective prisms and lenses. And remember, there's an APC, so it's not 'insane' for 'only 10mW' only 10mW was needed, so the APC holds it steady at 10mW, which is why removing the APC gives 25-35mW of output power.

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It doesn't change facts that it's very low effective, about FAC - yes, I though about it since as I saw there is alot of corrective lenses but anyway - you are right, it isn't needed, I know about APC aswell, still, even somehow reaching 35mW on these won't change my first words.

And remember, my posts are pure speculation, since I never had such module and the only source of informations are these pictures, but I will (atleast I hope so) soon.

There is no need to remove the APC, that makes for pretty unstable output. The pot I mentioned controls the diode current and that was confirmed by someone who figured out the serial interface. Just give it a few turns clockwise for more power. The max I was willing to try was 3 turns, but then I backed it down to two. The driver gets pretty warm. The stock heatsink is fine if it's open to the air.

-Tony

Cyparagon said:

Has anyone measured the diode current?

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As promised, I have received module from twhite828 (thanks!) today, it has "two dots" one small and the second one normal but who cares, ok so I did measured diode current with APC offline:





It's 1,88A after warmup:

#Edit
It's 1.46~~A with APC online, but I have just removed it permanently, also I was unable to get more juice from this driver than 1.9A so I will have to connect diode to the extended power source, old driver will still have control over TEC's but the second one will power up a laser diode.


so if we believe Chris:

heruursciences said:

These lasers have 3-5W diode inside of them, You should feed it 3-4A

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These diodes are running quite low powered, so there should bo no problem to increase current (even if it's only 2W diode, we should be able to run it stable at 2,5-2,7A).

That's just first day of testing, I will get everything from this module, until it dies or something happen to it.

Ok, I did some tests, disconnected diode from laser driver and powered it by other source, the old driver was connected just to take care of diode/crystals temperate, but I think it's controlling it only to get max power at 1.8A~~ I came to over 2,5A and instead of getting more power, it was decreasing, current monitor was done by two seperates modules, it was about 2,8V !! at 2.5A.

Sorry, I've got only pictures of powering it up by 1.9A, the one disconnected end of cable, is VCC of diode driver, the second one is ground.








So I'm pretty sure that it's temperate fault, well, it's or the diode is quite "retarted", not sure.

So did anyone manage to mod one of these effectively?

midias said:

So did anyone manage to mod one of these effectively?

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Mod it to what? They work fine as they are although most tend to have some extra spatter or dots. That's something you'd need to adjust the crystals to change.

MarioMaster said:

Mod it to what? They work fine as they are although most tend to have some extra spatter or dots. That's something you'd need to adjust the crystals to change.

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To use an external current source for the diode and use the factory tec controller. Or any other neat things that may be worth trying out.

.3lite did that, and didn't get any useful results - so I'd say it's not worth trying to rig up a second driver for more current.

MarioMaster said:

.3lite did that, and didn't get any useful results - so I'd say it's not worth trying to rig up a second driver for more current.

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Thats what I read above I was just wondering if he continued his research.

Cant remember exactly, but im sure I read somewhere that its not a good idea to have the lids of these 473's because the LBO crystal is hygroscopic and absorbs moisture.

^It takes several months for it to be a problem.

I got one of these a few days ago, and finally got a chance to play with it extensively today. After building a harness so I could run it with the driver halves separated so I could actually get to the pots with it running, I managed to get the stable feedback regulated output up to 24mW. Any higher than that and it never would stabilize, it would wander between 15mW and wherever the upper range was set. The driver on mine is v5.0 though. so tweaking it was a lot harder than just adjusting the one pot mentioned at the beginning of this thread. On mine I pretty much had to fine tune all of them on the driver to achieve that high of a stable regulated output and have the green LED go off.

Here it is with a ~280mW 650nm, this 473nm doing 24mW, and I forget what power that green is. There's also a 50mW 405 pen in that pic but it got drown out. heh.



Next on the list.. trying to do something about the divergence.

midias said:

Thats what I read above I was just wondering if he continued his research.

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It's quite difficult - it requires to control 2 TEC's + feedback from their's thermistors in order to achieve good temperate with higher pump power, I can tell you right now that the the power output is depending mostly on the crystal temperature* as well as keeping the diode wavelength at some specific value (using TEC, lower temp = lower wavelength, higher temp = higher wavelength).

*I have disconnected once TEC of the crystal and I was trying to control it without knowing the temperature (so without feedback from the thermistor) and for sure I know that crystal temperature at about 0-5C was inefficient and below that temperature the crystal started to getting iced (it was for sure predictable).

Tackled the divergence issue today on mine. The results weren't quite as good as I had hoped, but still a drastic improvement. I got the divergence down from 7.87mRad to 1.02mRad.

My solution was similar to Xplorer877's but not exactly. The method I ended up using was to use the front of an aixiz module which I machined a little shorter to fit in the space available. I used scavenged optics from a 532nm pointer as well for the rear fixed lens of the collimator. This was centered and glued in the diode pocket in the aixiz module. The front lens is the standard aixiz acrylic, with the housing shortened to be able to screw close enough to the fixed lens to focus properly.

Here's some blurry camera phone pics of the finished product.





And the most interesting thing though.. After doing this modification.. I managed to retune the driver and got 30mW of stable regulated output when before it maxed out at 24mW before going unstable.. :thinking: I think it is probably good for more but I don't want to push it TOO far. It's my only 473nm for the time being so I don't want it to die an extremely quick death.



And lastly, before and after shots of the dot at about 30' or so.





It took some work but I can't really knock it though.. 30mW of 473nm with 1.02mRad divergence still is in no way shabby for the $87 it cost me.

^ Nice mods I will have to try that. Are you still using the photo diode in the tip? In tuning it did you only have to adjust the single pot?