[martinmunk]

I did basically this exact same thing at work a few years ago.

For time-correlating audio measurements around the office buildings I needed a analog reference signal in sync.

So I drew up a PCB design with a toslink in/out connector, and a connector for a SFP module and just a lvds driver in between. It worked straight away (more luck than skill) I could then re-use network fibers already run around the basement, and convert it to analog in the MDF rooms of each building, and run the analog signal up to the 3rd floor through existing RJ45 cables.