Design and analysis of wide flatness gain bandwidth based on serial hybrid fiber amplifier

A flat and wide gain bandwidth based on serial hybrid fiber amplifier is experimentally demonstrated in this study. The proposed amplifier consists of a serial combination of erbium doped fiber amplifier and Raman fiber amplifier. Low pump power of 30 mW of 1480 nm pump power is used as a pump unit for erbium amplifier. While 1495 nm pump unit with maximum pump power of 475 mW is used as a pump power for Raman amplifier. At the optimum pump power values and at small input signal power of -25 dBm, a gain flatness bandwidth of 81 nm (1525-1606) with an average gain level of 25 dB is achieved. On the other side, wider gain flatness bandwidth of 100 nm (1520-1620nm) with an average gain level of 14 dB is achieved at large input signal power value of -5 dBm. The overall gain spectrum and the gain dynamic range are tested under different input signal power range. In addition, an experimental demonstration of an efficient flatness gain bandwidth is presented. A double pass serial combination of erbium and Raman fiber amplifiers is employed. A pump power unit of 1480 nm with low pump power value of 30 mW is used for erbium amplifier. While a pump unit of 1495 nm with a pump power value of 300 mW is used for Raman amplifier. Under the optimization conditions, at low input signal power of -30 dBm, a flat bandwidth gain of 77 nm from 1530 to 1607 nm with an average gain level of 27 dB is achieved. At large input signal power of -5 dBm, wider flatness gain bandwidth of 93 nm from 1524 to 1617 nm with an average gain level of 11 dB is obtained. Finally, both of gain dynamic range and the overall gain spectrum are recorded at the variation of the input signal power.