Most of the heat from the LDs in burners is conducted away rather than radiated. The open heatsink LDs in DVD burners are installed in sealed enclosures so the airflow is minimal.
As was mentioned, usually the faster drives require a higher power LD because the time the data location us "under the gun" is less with higer speed units. Therefore, more heat must be applied to get the same effect.
I've got a team of people working on this project that includes a laser. I'm sure I can find some ECE or EE people to carefully do this for me. If I follow all the instructions very carefully.... I should be fine right ^_^
I just want to add I do not believe there is any difference in any of the open can diodes used in DVD burners. If you want to try an open can I suggest the Pioneer PL-112D burner as I think it is the easiest to harvest. If you want a 16X diode, then there are still a few left in the GB. Look in the Buy/Sell section of the forum.