We demonstrate a diode-pumped Yb-doped fiber master oscillator power multimode amplifier. The multimode output beam is converted to singlemode by a two wave mixing process in an infrared sensitive photorefractive crystal (Rh:BaTiO<sub>3</sub>). Up to 1W singlemode output is achieved by compensation of thermally-induced phase fluctuations in the fiber.

© 2003 Optical Society of America

PDF Article