5 ms·

Naive question: Was fiber always digital? I could imagine varying the intensity of the a laser signal to send sound.

by ape4 2y ago

zabzonk 2y ago
but ... why?
- ale42 2y ago
  Simpler and cheaper electronics, probably.
declan_roberts 2y ago
I can't imagine that subtle light intensity would survive the various light amplifiers used along the way.
- ooterness 2y ago
  Analog signals won't survive a 1000km undersea cable, but for a few kilometers you don't need amplifiers at all. The loss-per-meter of optical fiber is much lower than a coax cable.
- wildylion 2y ago
  This is exactly how hybrid fiber-coax works for CATV.
- deleted 2y ago
  [deleted]
ooterness 2y ago
Radio-frequency over fiber (RFoF) signals are usually analog. By intensity-modulating the laser, it's relatively easy to convert a GHz-wide analog signal from electrical to optical and back. https://en.wikipedia.org/wiki/Radio_over_fiber https://en.wikipedia.org/wiki/Radio_over_fiber https://www.rp-photonics.com/radio_and_microwave_over_fiber.html https://www.rp-photonics.com/radio_and_microwave_over_fiber....
deleted 2y ago
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ssl-3 2y ago
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

Naive question: Was fiber always digital? I could imagine varying the intensity of the a laser signal to send sound.

by ape4 2y ago

Naive question: Was fiber always digital? I could imagine varying the intensity of the a laser signal to send sound.

zabzonk 2y ago

but ... why?

ale42 2y ago
Simpler and cheaper electronics, probably.

declan_roberts 2y ago

I can't imagine that subtle light intensity would survive the various light amplifiers used along the way.

ooterness 2y ago
Analog signals won't survive a 1000km undersea cable, but for a few kilometers you don't need amplifiers at all. The loss-per-meter of optical fiber is much lower than a coax cable.
wildylion 2y ago
This is exactly how hybrid fiber-coax works for CATV.
deleted 2y ago
[deleted]

ooterness 2y ago

Radio-frequency over fiber (RFoF) signals are usually analog. By intensity-modulating the laser, it's relatively easy to convert a GHz-wide analog signal from electrical to optical and back. https://en.wikipedia.org/wiki/Radio_over_fiber https://en.wikipedia.org/wiki/Radio_over_fiber https://www.rp-photonics.com/radio_and_microwave_over_fiber.html https://www.rp-photonics.com/radio_and_microwave_over_fiber....

deleted 2y ago

[deleted]

deleted 2y ago

[deleted]

ssl-3 2y ago

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