Dual-wavelength LD's - Can you run em together?

Can one run both LD's in a dual-wavelength can in paralell for more burning power in a laser-engraver?
I am thinking mostly of the IR/RED combos you find in some DVD-burners.
Strapping one to my cnc I find it cuts the plastic sheets I need almost perfectly, but a tiny bit more power would be good. It is tempting to power up the IR LD in paralell for that little extra oomph...

One concern is the fact that even my new lovely safetyglasses don't protect me from IR. Their OD gparh shows they go back down to maby OD 0.5 at around 800 nm and as far as I know IR LD's are often in the 830 nm range.

Also, the longer wavelength reduces absorption making it less usefull for burning. I guess I simply need a BD diode

The Ir laser is only a reading laser to read the data. It's only around 2-10mw at the most.

On a DVD-RW it can't be that weak?
After all, it reads and writes both DVD's and CD-R(W).

You can't focus both onto the same point though: the focal distance is different for the wavelengths, so you would have to adjust the lens whenever you switch between them, and using both at the same time can't work.

Good point Benm.
The difference in red, green, blue is usually not that big a deal but that covers the range 400-750 nm. 830nm really isn't that far out is it? Red and IR are further apart though with 650/830 vs red and green at 532/650.

I'm not sure its only due to the difference in refractive index between the wavelengths though... perhaps the diode chips dont have the exact same distance between output edge and diode window either. In a drive this would not be a problem as the optics have to be constantly adjusted to keep focus on the disc, and you only use one at a time depending on the type of disc.

Depending on the distance to focus point I see my red focuses over a quite long range. The further away the "longer" the area of focus is. At 3" it's atleast 1/3" long with well focused spot. (And burning right through a 1mm gray plastic housing at 192mA.)
I was just hoping to add a bit of oomph with the IR.