Diodes vs. Modules?

So I looked into this a little more, but can someone help me understand more what these two parts do in a laser?

Like, is the diode the part that emits the color of light? or is it simply something that channels the light? If it's the second case...would that make the module what creates the wavelength for a laser's light?

Please Help!

The diode is the laser.

Since the cavity is so short, you need a lens to correct the beam.

Since the lens needs to be able to be focused and held at a fixed distance, we use modules that hold the diode and the lens at the right places.

Did you not read the thread I posted for you? :tsk:

http://laserpointerforums.com/f51/i-want-build-laser-thread-52972.html

Sorry about that, I had posted this one in another section thinking this was the proper one..
My bad! I read it now, it's very informative! Thanks!