... I'm driving 975nm-diodelasers with 9Watts or 25Watts @9Amps and TTL-switching through a MOSFET with a group of LM317 / LM350 / LM338 configured as current regulators and running parallel to sum the curent.
It's a simple circuit - you can find some infos in my lasercutter-WiKi: http://www.reprap.org/wiki/Laser_Cutter_Notes
I've made this Wiki some years ago then with 5Watt-diodes running with 5Amps max, but you can replace the LM317 (until 1.5Amps, continuous current 1A) by LM350 (until 3Amps) or LM338 (until 5Amps) to receive more current per chip.
My actual driver has two LM317 and three LM338 configured to 1A+1A+2A+2A+2.5A, which i can switch together in any combination for predefined max current from 1A to 8.5A for different diodes or running the 'big' diodes with lower current than the max. spec of the diode says (what will enhance the lifetime until 'forever').
The 'finetunig' is made with TTL-level (0-5V) through an opto-coupler and PWM-switching the MOSFET, that drives the current through the LM's and the laserdiode.
Recently I've found an analog circuit with a LT1215 OP, that can drive the same LM-configuration with analog voltage level until 1MHz clocking rates! and will solder and test this in the next weeks ...
Viktor