High-power 1560 nm single-frequency erbium fiber amplifier core-pumped at 1480 nm

Abstract High-power continuous-wave single-frequency Er-doped fiber amplifiers at 1560 nm by in-band and core pumping of a 1480 Raman laser are investigated in detail. Both co- counter-pumping configurations studied experimentally. Up to 59.1 W output 90% efficiency were obtained the fundamental mode linear polarization co-pumped case, while less power achieved counter-pumped setup for additional loss. The amplifier performs indistinguishably terms linewidth relative intensity noise frequency range up 10 MHz both configurations. However, spectral pedestal is raised co-pumping, caused cross-phase modulation between pump signal laser, which observed analyzed first time. Nevertheless, 34.9 dB below peak, has negligible effect most applications.