fiber optics against copper

Kicking it around using rhetorical questioning....

Amplitude modulation? Variable brightness going in, variable brightness coming out. Er, what about attenuation and losses within the fibre-optic? Getting a repeatable 0-100% range calibration might prove difficult.

Frequency modulation? Variable colour going in, variable colour coming out. Yep. That would work in principle. Interesting transmitter and receiver designs up for grabs. Might not have been done before, and might be patentable.

Multiplicity of signal paths? Well, the fibre is down to 1 signal running analog, whereas it has a much larger capacity running digitals.

So, though it isn't usually done, it could be done, though why would one want to? Copper and a 4-20mA signal might be a more economic choice for one signal path. Fibre comes into its own when a lot of signals have to travel a long way, which is where it wins Mizzaire Ouverte [Whist card-game term] against copper.

Fiber optics have clear edge over copper when faster reliable high bit rate transmission is required. Its popularity is day by day increasing.

Will join the site one day. http://fiberopticcableprocess.blogspot.com/

I suppose it depends on what sampling frequency is fast enough to be considered analog?

I have been playing with interferometer based fiber sensors to measure temperature, strain, and vibration. By a strict definition of analog, I suppose these sensors are indeed analog (mechanical motion directly translated to light signal). But the signal processing unit after the photo detector is immediately digital, so I guess on a system basis it is still digital....

Here is one example....

http://scholar.lib.vt.edu/theses/available/etd-12212006-203046/unrestricted/dissertation_zhuang2006.pdf