Gain and noise figure performance of an EDFA pumped at 980 nm or 1480 nm for DOFSs

Erbium-doped fiber amplifier (EDFA) is widely recognized as one of the most important optical amplifiers in distributed optical fiber sensors which has been able to compensate the loss of the optical power. The 980 nm and 1480 nm are the most efficient pumps for amplifying the 1550 nm signal in EDFA. This paper presented an investigation for influences of pump power, signal power and EDF length on the gain and noise figure in an EDFA which pumped by 980 nm and 1480 nm pumps. It is also a comparison for each of the created gain and noise figure at the forward, backward, and bi-directional pumping configurations, separately. The effects of Rayleigh scattering, temperature, homogeneous interactions between Erbium ions and the amplified spontaneous emission are considered. As a result, Bi-directional pumping shows the highest gain value, and forward pumping presents the lowest noise figure for each pump. Moreover, backward pumping creates the highest noise figure and forward pumping generated the lowest gain value. The gain of 980 nm pump is higher than 1480 nm up to 5-m EDF length and for longer lengths, it becomes vice versa. The 980 nm pump caused a lower noise figure than 1480 nm for EDF length up to 10 m and it becomes vice versa for longer lengths.