All-solid-state neodymium-based single-frequency master-oscillator fiber power-amplifier system emitting 55??W of radiation at 1064??nm

We demonstrate a master-oscillator fiber power-amplifier system consisting of a diode-pumped monolithic nonplanar ring oscillator as the master oscillator and a Nd:glass double-clad fiber as the power amplifier. The system emits up to 5.5 W of single-frequency radiation at a wavelength of 1064 nm with an M(2) value of ~1.1 . The optical emission spectrum is investigated with respect to the background of residual amplified spontaneous emission. Spectrally resolved amplitude-noise behavior is examined. Further power-scaling possibilities are discussed.