Envelope Detector +fiber optic

I'm building an SCR based powersupply and I'm working through some of the control circuitry at the moment. I have it breadboarded and it works fine, now I need to modify it a bit.
The supply is for a tesla coil and I'd like to be able to control it from a safe distance. I could just keep the supply at a remote location and run the output straight to the coil, but I'd rather not have to haul the supply around.

I'm planning on using a 50' fiber optic cable for the firing angle control. The problem lies with the fiber optic reciever which has a minimum frequency of ~200kHz. My plan is to take the 120Hz variable width from the original circuit and 'and' it with a higher frequency signal. then use an envelope detector on the other end to just get the variable width signal out.

Does it look like it will work?

That should work, but you don't really need a diode, just a low pass filter on the input of the transistor will do.

You don't live in a town called Eureka do you?.