H
Member
This gets asked often enough that I wrote down my notes.
1）The laser relative intensity noise sets a floor that no amount of RF gain can fix.
2）Shot noise at the photodiode scales with photocurrent, so more optical power helps up to a point.
3）Thermal noise in the post-detection amplifier dominates at low photocurrent.
4）For a given link, there is an optimal optical power that minimises the total noise figure.
YMMV depending on the project.
1）The laser relative intensity noise sets a floor that no amount of RF gain can fix.
2）Shot noise at the photodiode scales with photocurrent, so more optical power helps up to a point.
3）Thermal noise in the post-detection amplifier dominates at low photocurrent.
4）For a given link, there is an optimal optical power that minimises the total noise figure.
YMMV depending on the project.