High power two-stage single frequency PM fiber amplifier

We demonstrate a two-stage single frequency polarization maintaining Yb-doped fiber Amplifier at 1064nm. The gain is 7dB and 17.6dB for the first and the second fiber amplifier. The output power is 17.3W with 62.8% slope efficiency for second fiber amplifier and the polarization extinction ratio is better than 24.3 dB.