Answer and Explanation:
the electronic devices always have some noises present in the signal
there are some important considerations in optical fiber communications these are.
- the noise which is contributed by transmitter are electronic random noise, low frequency noise
- noise which is contributed by laser are relative intensity noise, mode partition noise, conversion of phase noise to amplitude noise.
- noise contributed by photo detector are quantum shot noise, shot noise from dark current, avalanche multiplication noise.
PRINCIPLE OF POPULATION INVERSION :
The principle of population inversion is defined as for production of high percentage of simulated emission for a laser beam the number of atoms in higher state should be greater than lower energy state