High gain and low noise O+E bands fiber amplification based on hybrid bismuth-doped fiber

In this paper, we propose and demonstrate a hybrid bismuth-doped fiber approach for broadband amplification in the O + E bands. The bismuth-doped fibers were fabricated by the MCVD process combined with solution doping technique. The amplification performance was investigated by the two pump wavelengths of 1240 nm and 1270 nm combined with different pump configurations. The results show that the maximum gain of 38.2 dB with the NF of 3.7 dB was achieved at 1350 nm by the bi-directional pumping configuration. Furthermore, the hybrid bismuth-doped fiber was demonstrated to improve the gain in E-band and maintain the gain flatness between O-band and E-band. A wide bandwidth of ∼150 nm (1310 nm–1460 nm) was achieved by the hybrid fiber, with a gain >15 dB, gain flatness of 8 dB, and NF of 4.1 dB–5.7 dB.