Patent ID: 7876803

Claim:
A method comprising: providing a rare-earth doped large-mode-area (LMA) fiber gain medium; configuring an optical signal path that extends through the fiber gain medium such that the optical path forms a ring laser having a signal beam; optically pumping the rare-earth doped LMA fiber gain medium; forming a free-space signal beam in the optical signal path of the ring laser; Q-switching the free-space signal beam outside the rare-earth doped LMA fiber gain medium at a timing controlled by an electrical signal; extracting, from the free-space signal beam, an intermediate optical signal pulsed output beam having a first wavelength, wherein the Q-switching of the pulsed output beam is controlled by the electrical signal during normal operation of the extracting of the pulsed output signal and independent of cavity length; and wavelength converting the intermediate optical signal output beam to form a second signal output beam having a second wavelength that is different from the first wavelength of the intermediate optical signal output beam, wherein the second signal output beam has a power of at least 2500 Watts.