SFP is the modern standard for pluggable laser modules. RJ45 sfp modules exist, but only for 1G and 10G. There’s also DAC cables for sfp, but those are limited to 2-3m, and the point was to focus on the benefits of fiber. Maybe the economies of scale necessitate some modern silicon photonics like a fiber on package option, but then you have repairability issues.
The minimum bend radius is mostly because of complete internal reflection, fiber is very flexible, and it’s not really possible to break an armored fiber cable by hand. You do have to worry about dust on the ends, though.
Toslink is cool, but it’s a very low bandwidth standard, less than 1gbit. You need proper glass fiber and lasers for high bandwidth.
I think you are mixing up SFP and optical fiber. SFP modules with copper wires exist, and are common. (e.g. SFP 1000base-T modules)
You can also use optical fiber without SFP, like the toslink connection.
Optical fiber also has issues with requiring a larger minimal bend radius, because they easily break. So you have to handle them more carefully.
SFP is the modern standard for pluggable laser modules. RJ45 sfp modules exist, but only for 1G and 10G. There’s also DAC cables for sfp, but those are limited to 2-3m, and the point was to focus on the benefits of fiber. Maybe the economies of scale necessitate some modern silicon photonics like a fiber on package option, but then you have repairability issues.
The minimum bend radius is mostly because of complete internal reflection, fiber is very flexible, and it’s not really possible to break an armored fiber cable by hand. You do have to worry about dust on the ends, though.
Toslink is cool, but it’s a very low bandwidth standard, less than 1gbit. You need proper glass fiber and lasers for high bandwidth.