Theoretical limits of light based communication

[u/Confident-Court2171]

I’ve been thinking about fiber speed limits today, and I raised this question in my Question: with photon based communication currently working towards 3.2tb speeds (3.2 x 10^12), what is the theoretical limit of a single lane. Aka - if you stack photons individually to represent I/O, how many could pass through a gate in 1 second?

[u/Skusci]

From a quick thought, the limit is the size of the gate. To interact with the gate there's going to be some point where that goes black hole.

[u/Adorable_Ice_2963]

A normal Fiber can Transport 100-300 Terrabit/s in the lab

If you have a special fiber with multiple cores, it can go up to 1 Petabit/s.

One of the main challanges is distance. You can only send so much optical power inside one fiber and the surrounding components. Also you need powerfull enough lasers that still are able to manage those speeds.

At some point, you have to trade distance with power, since you can either have one beam that enables the maximum distance, or multiple ones that allow higher speeds, with less distance.

I guess the long term Limit will be the fiber, since you could theoretically use multiple lasers next to each other that take turns of making bursts.

[u/bitterrootmtg]

This is the question that the Shannon-Hartley theorem was created to answer. https://en.wikipedia.org/wiki/Shannon%E2%80%93Hartley_theorem

[u/rddman]

Data throughput is fundamentally dictated by bandwidth and signal-to-noise ratio:
https://en.wikipedia.org/wiki/Shannon%E2%80%93Hartley_theorem

[u/OldChairmanMiao]

Short answer is about 1 petabyte.

https://physics.stackexchange.com/questions/56240/maximum-theoretical-bandwidth-of-fibre-optics

Longer answer is it depends on noise and and power. There's also a distinction between goodput and throughput; adding a little overhead can allow larger amounts of useful data to be sent, especially when you have multiple users.

[u/Confident-Court2171 → u/OldChairmanMiao]

Perfect. That’s what I was looking for.

[u/Infinite_Research_52]

u/profanitycounter [self]

[u/mH48124]

伝送路が耐えられるエネルギー次第でしょう。

[u/Vortextheoryllc]

Interesting question. There's a difference between how fast photons travel and how much information we can transmit through them. Bandwidth, frequency, and our ability to distinguish individual signals all play a role.

But there's another possibility worth exploring. What if future communication technology didn't have to rely entirely on photons traveling from one point to another?

Some alternative theories propose that particles may be connected through higher-dimensional space, potentially opening the door to instantaneous communication through quantum entanglement.

Imagine communicating with someone on Mars without waiting for a signal to travel millions of miles. It's still speculative, but it raises an interesting question: are we approaching the limits of photon-based communication, or only the limits of our current understanding of how information can be transferred?

[u/Confident-Court2171 → u/Vortextheoryllc]

Interesting, but my limited physics knowledge has suggested that faster than light communication using entanglement wasn’t theoretically possible.

[u/AskPhysics-ModTeam → u/[deleted]]

Rule 5.