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

That's odd then - W3, when turned fully CW, seems to have made the start-up delay almost completely gone.

And regarding the time to start up... okay, that makes more sense. I suppose I should try that... a piece of laser info a day is always good!

Unfortunately, I did not make a harness yet. I didn't have much time, so I sort of just fiddled with it gradually. How did you make your harness? Just solder wire to the pins and stick the other end in the holes?

(By the way, appreciate all the help. +1)

My harness is super high tech. I cut cdrom audio cables in half.



Kind of bugs me that yours is only doing 3mW though. With feedback they should do at least 6 or 7 minimum, even with bad modes.

If your lucky you just went the wrong way with W2 and turned the power down, if your unlucky, you went too far the other way, exceeded the optical power the pump is capable of, and degraded the pump facets.

Well, I tested it right when I first got it and it was still only doing 2-3mW, if I remember correctly. Although... I *may* have turned the pot on the PSU up higher than 5V... would that have done the damage? XD I turned it up because just that - it wasn't doing much, and I figured that would help me.

If so... it means that the driver is probably damaged, but not the head, yeah? Either way I am sorta screwed (a bit), but....

Anyway, so how would you suggest that I test to see if I hurt the optical pump or not?

If it was always doing 3mw or so, then nothing was probably hurt. The most that switching PSU can put out is around 6V, so even all the way up, it's unlikely to hurt the driver. Though turning it up shouldn't really add any benefit either, only generate more heat, so it's best to just leave that at 5V.

I'd just make a harness then slowly play with w2 while it's running and on a LPM and see if you can get it up any higher. Have you tried removing the feedback pickup from the front of the head? I don't advise running it long like this despite what DLMB says, since i've killed two by doing it.. But it won't hurt anything for a short time. If you only get around 3mW even with it off, it probably means you got unlucky and got one that already has pump degradation.

Which one exactly is the feedback pickup? Is it the thing with the photodiodes on it? Or what?

And I will play around with it once I get home (house-sitting now).

It's the round thing that's attached to the front of the head with the red and black wires coming out of it.

But if I remove that, won't the photodiodes not receive data anymore?

So something odd just happened... when I turned on my laser after making a harness so I can adjust the pots (didn't touch the pots at all), my LPM is giving a reading between 7 and 8mW... I didn't adjust anything at all, either... odd, eh?

EDIT: And it's definitely not an LPM issue because I just checked the calibration on it with another laser of nearly the same wavelength.

EDIT #2: Now, after turned it on again for a second time (had to turn it off to check the calibration on my LPM) it dropped down to 4mW again. That was really odd .

EDIT #3: And what's odd is that the green stabilization light doesn't want to turn off. I will keep an eye on it... but how long should it take for it to stabilize?

EDIT #4: I think I know what may have caused the drop... I think my LPM's interior warmed up rather drastically due to the calibration check I did.... So I will turn off the LPM and let it cool off for a while. Will test again later.

EDIT #5: Yep! My hypothesis was correct - after leaving my LPM off for a bit and then turning on my 473nm at another target (to let it stabilize for a while, even though the green light is still on), I turned the LPM on and now it seems to want to stay somewhere between 7-8mW! Gonna leave it on for a while longer to see if it eventually *does* stabilize.

Wolfman29 said:

But if I remove that, won't the photodiodes not receive data anymore?

Click to expand...

That's the point. When you remove the feedback, it runs the pump flat out, meaning you get as much 473 out as it's capable of with your current driver settings, as opposed to the pump getting constantly adjusted by the driver to maintain a constant optical output.

I also forgot you had a DIY LPM. How certain are you of it's calibration to 473nm? The coatings you use on the tec matter a lot.

And also. I think you were warned not to put the sensor in the same box with the electronics or this would happen. heh.

Well, I have tested it on a 532nm and a 405nm and a 445nm, and all the readings I get from those seem to be pretty accurate. The only thing that seems to throw it off is the heat that the sensor is receiving, which was a design error -.- Might remove the sensor today and see if I can get better readings.

EDIT: So I took off the lid so that the inside can cool off better (more accurate reading, I would hope?) and now I am going to turn it off again, wait a while, then do another reading.

EDIT 2: And yes, I was totally warned of that Just didn't think that it would leave such a huge discontinuity .

EDIT 3: So I just turned off the 473 after a good 20 minute run. It did not seem to want to "stabilize". The green light never turned off. Also, Further, even the CNI head was getting rather hot. What is the safe duty cycle on these?

Wolfman29 said:

Well, I have tested it on a 532nm and a 405nm and a 445nm, and all the readings I get from those seem to be pretty accurate. The only thing that seems to throw it off is the heat that the sensor is receiving, which was a design error -.- Might remove the sensor today and see if I can get better readings.

EDIT: So I took off the lid so that the inside can cool off better (more accurate reading, I would hope?) and now I am going to turn it off again, wait a while, then do another reading.

EDIT 2: And yes, I was totally warned of that Just didn't think that it would leave such a huge discontinuity .

Click to expand...

Seem to be? :thinking: You have compared it a known calibrated LPM right? Otherwise it's just a guess and it's only real use is telling what lasers are stronger than each other... Not what they actually measure.

While no, I have not compared it to a calibrated LPM, I am pretty confident that my readings are rather accurate. I have looked at various charts for given powers with given strengths, tested multiple diodes of the same wavelength at the same current and gotten averages to calibrate it, I have tested multiple wavelengths, and all fall within "decently" calibrated values, i.e. within 5-10%.

EDIT: So while, yes, it *is* possible that all my readings have been off, the unlikeliness of that is staggering, given the amount of testing and comparing I have done.

EDIT 2: So I took off that front thing... with it off, I noticed that there may have been some alignment issue or something, because some of the light emitted seems to be blocked by the interior, i.e. the window through which the beam passes is off by a millimeter or so. But, back to what I was saying - very little to no change from removing the front thing.

I just bought one of these little guys this morning. It's the first laser I've purchased in a loooooong time, but for $75 I just couldn't pass it up. I just wanted a nice stable 473nm laser. I'm not power hungry, I have a 10W argon for that, I'm just a bit of a wavelength whore


Next on my agenda is to get my solid-state 488nm laser working again.

I love my 473...it make you realize how violet our favorite 445 diodes really are.

A while back some 488nm coherent OPSL's passed on ebay, but the guy didn't ship outside the US. I wish I had one of those...
I haven't had 445nm next to my 473nm, but in a while I may be able to add 457nm.

Bluefan said:

A while back some 488nm coherent OPSL's passed on ebay, but the guy didn't ship outside the US. I wish I had one of those...
I haven't had 445nm next to my 473nm, but in a while I may be able to add 457nm.

Click to expand...

Seems they're still available: remag2010 | eBay

Also, this: http://www.ebay.com/itm/COHERENT-SA...490?pt=LH_DefaultDomain_0&hash=item415a7c43c2

-Trevor