High-gain-coefficient L-band EDFA using 1530nm-1550nm band pump

Abstract

The long wavelength-band erbium-doped fiber amplifier (L-band EDFA) using 1530nm-band pumping has been proposed and studied. A 1530nm-band pump source is built using a tunable light source and two C-band EDFAs in cascaded configuration, which has a maximum output power of 20dBm. An optical tunable filter is used at the end of this pump to prevent ASE noise. A 65m-long EDF is used for L-band amplification. Gain coefficient and noise figure (NF) of the L-band EDFA are calculated and measured for pump wavelengths between 1530nm and 1560nm. They are decided on the condition of pump power required for 15dB flat gain in signal wavelength band between 1571 and 1601nm. The gain coefficient with a 1545nm-pump is 2.25 times as large as with a conventional 1480nm-pump. It indicates that the L-band EDFA consumes low pump power. Calculated gain result reflects well the trend that gain coefficient in 1530nm-band is about twice than 1480nm-pump like experimental results. The noise figure of 1530 -pump is at worst 6.36dB, which is 0.75dB higher than 1480nm pumped EDFA. The calculated result for theoretical minimal noise figure says that measured values are exact. Gain spectra as a function of a pump wavelength have bandwidth of more than 10nm so that a broadband pump source as well as single wavelength pump can be used as 1530nm-band pump. The L-band EDFA is also tested for WDM signals. Flat Gain bandwidth is 32nm from 1571.5 to 1603.5nm within 1dB excursion at input signal of 10dBm/ch. These results demonstrate that 1530nm-band pump can be used as a new efficient pump source for L-band EDFAs.