45 W Single Frequency Er-Doped Fiber Amplifier at 1530 Nm

A high power continuous-wave single frequency 1530 nm Er-doped fiber amplifier is demonstrated with polarization-maintaining single mode fiber as gain medium. To achieve the > 50% population inversion required for efficient 1530 nm amplification, core pumping with a 1480 nm Raman fiber laser is utilized. The advantage of 1480 nm core-pumping over usual 9xx nm diode cladding pumping is proved with numerical simulation. Maximum single frequency 1530 nm laser of 45.5 W with an amplified spontaneous emission suppression ratio of 46 dB is obtained at an incident 1480 nm laser of 60.7 W, corresponding to an optical efficiency of 74%. To the best of our knowledge, this is the highest reported single frequency 1530 nm laser, which will be used to pump an acetylene-filled hollow-core fiber laser.