I need to modulate a LED quickly (multi-megahertz range) on/off. It's a high-power LED. I have had some trouble locating any well-known methods to do this. Simply switching the voltage with a FET turns on the LED quickly but the fall-time will suffer, and to solve that, I guess there are some different solutions, for example maybe switching in a reverse bias for a short while? Any ideas?
I think the underlying problem with the turn-off is that the charge-carriers make the p-n junction act a bit like an inductor in that the current will keep on going for a short while after turning off the voltage gradient, but I haven't found any reference on this.
I know that a laser-diode can be modulated much faster.
EDIT: since this question has a lot of views, let me add some context - the application for this was a 3D camera using a time-of-flight CMOS sensor. Essentially, you send out light, it bounces on the scene to be imaged, and the image sensor can discern the phase difference between the sent light and received light. Faster and deeper modulation means better resolution and less noise in the 3D image. In this particular application, 20 MHz was the target modulation rate.