Fiber optic FM modulation

[Bibiricat]

Hello.

I find myself asking you for help with one of my problems.
What i need to build is an audio transmitter that will transmit via fiber optic a frequency modulated signal to a receiver that should be able to rebuild the signal.

The problems i am having is that i can't find a schematic that will generate a 100kHz (or more) sine wave and could modulate that signals frequency based on a audio (max 20kHz) signal, and then transmit that through a fiber optic cable. I would also need a receiver that would take the fiber optic signal and recompose the audio signal.

Any help would be greatly appreciated.

[Zero999]

Just to be picky, this isn't optical FM because that would involve modulating the frequency of light which is possible with a tunable laser.

You need a 100kHz VCO but the problem is getting sufficient modulation at that frequency sinewave isn't easy. You could build a triangle VCO and use a wave shaper to get a sine output. Another option is a beat frequency oscillator. Build two RF oscillators, one with a fixed frequency of 1MHz and a VCO with a centre frequency of 1.1MHz and a range and put them through a mixer. The output from the mixer will be 100kHz with no signal  and you'll only need to change the frequency of the VCO by +/-20kHz to give a sweep of 80kHz to 120kHz.