Fiber can indeed be used in a way that is close to coax, or twisted pair, or whatever. It just takes a different [block diagram] of stuff at each end for eithe

Fiber can indeed be used in a way that is close to coax, or twisted pair, or whatever. It just takes a different [block diagram] of stuff at each end for either configuration. It's not inherently digital at all. One of the earliest fiber implementations I ever saw the back end of with my own eyes was a municipal camera system. These were NTSC composite cameras with media converters to convert the electrical signals (over coax) to light signals (over fiber). It was analog, and dated to 1987 when the building was built. That kind of thing was not new even at that point and did not even begin to push the limits of the mediums. (And "digital" signals, too: We may tend to think of them as just on/off 1s and 0s, but they're seldom actually that simple in high-speed* signalling systems -- whether electrical or optical.) *: Whatever it is that "high-speed" means around the time of implementation