CNI OEM-F problem

[MIIKKKLLLL]

Hi all,


I own a 2W green CNI OEM-F laser head, built in 2013 with strange behavior.


First, the head is slow to warm-up the first minutes after power ON, even at 20°C ambiant room temperature (I'm not the only one in this case because this has already been talked here on PL). This is not the biggest problem.

The second problem here is about the modulation. The maximum power is reached at 3.8V (DC), then if you raise the voltage, the power decreases a lot.


The beam quality decreases too (loss of uniformity and increase of divergence).

I add that the head isn't misaligned, good TEM00 beam (or at least it looks like that at 25 meters).



In modulation, there is no problem if the duty cycle is low (<70%). Do you think it could be an overdrive of the pump diode ?


Does anyone have an other idea ?

Thanks !

[xabst]

Maybe, there is sth wrong with the cooling system. for example, the tec is in trouble and not work. so the temp. is not in control, and it needs a long time the get balanced, the balanced temp.is higher than normal, of course. when the voltage is higher and the heat is more, the temp. is higher, and the output power is down fast. that is what i think of the reason.

www.bestlaser-tech.com

[Laserpower]

HI MIIKKKLLL

Most sound like your Temp set point is to high. Than you over shot the right set point and the power will fall.

What drive do you run on this head ? ORg. CNI With or with out H-bridge. A Pic would be nice. :-)
Else can i say the pico driver is a Good stable driver compared to the Cni Drivers.

/Poul.

[MIIKKKLLLL]

I don't think it is a too high temperature issue as even at cold start (from 18°C ambiant room temperature), the power is low.

Here is a picture of the driver. Guess it is the old version without H-bridge (cooling mode only).




I would like to solve the problem using the original driver, not an other one .

[ams09]

Hi Mika,

Yes, the problem is the temperature management. This model has only one TEC and is very difficult to manage between the two crystals and diode. This is the low cost version avoid ...
For the modulation part, an adjustment may be possible on the driver, but your photo is not detailed enough to see it.
Note that the documentation on this game CNI product remains unclear.
I found this: http://www.cnilaser.com/PDF/OEM-F-532.pdf

Christophe.

[MIIKKKLLLL]

Hello Christophe,

Yes, I know ... I already tried to adjust the temp without good results.

If I don't find a solution by next Monday, I will contact CNI to ship back to them for repair !

Here is a more detailed picture :

[mccarrot]

Hmm, just faces a similar issue, upto 50% modulation I have almost no output, and with 100% modulation it slowly climbs from 0,6W to 1,2W.
Did you find out where the pots are for?

[MIIKKKLLLL]

It seems that you face an other problem.

Mine was a TEC driver fault -zero cooling-, so I had to ship the head+driver back to warranty.

Here is the driver schematic. I suspect the temp set point adjusted too low, leading to a slow warmup.


Edit : I can't upload the file on PL . Could you send me your email through PM ?