Acousto-Optic Modulation for Sound Transmission 

and also Doppler shift with light -- very nice and I learn new thing that I do not need DAQ system + software to get back the sound signal -- just use FM radio ! Thank you.

It was a standard 80 MHz AOM. Ideally, I would use an AOM in the range of FM Signals for North America. This AOM frequency is slightly below this FM range. Its been a few years and I do not recall the AOM;s make and model.

Looked like an Isomet 1205C to me(?)

We wanted to shift the audio signal to a high frequency of 80 MHz. This method makes the audio signal easier to recover and reduces the low frequency noises which may be apparent had the signal be modulated another way. In addition, the optics for setup where readily available in the lab.

The AOM has one beam at frequency v0 and a second beam with frequency v0 + 80 MHz.

This system can be done with fiber optics. So the distance is limited by laser power and fiber optic cables.

A 80 MHz waveform generator.

@@georgenoble4482 Can I get the product(function generator) details ?

From where I can buy this RF Generator to drive AOM ?

@@prk310 It's a standard waveform generator that is readily available used or new. You can Google 80 MHz waveform generator also.

Depending on your AOM model, you may need to amplify the 80 MHz signal