Extended-cavity operation of rare-earth-doped glass waveguide lasers

Channel waveguides fabricated in Nd-doped glass were used as gain elements for extended-cavity lasers. End-fire pumping was performed with a Ti:sapphire laser operating at 807 nm. The 4-nm FWHM output spectrum was centered near 1057 nm. Slope efficiencies were typically 4-11%, with thresholds near 20 mW. Active mode locking and Q switching were separately performed; mode-locked pulse widths were roughly 80 ps FWHM. Q-switched peak power was 1.2 W. The cw output narrowed to 7 GHz and tuned over a range of 24 nm when a grating provided feedback; single-frequency operation resulted when a high-reflectivity étalon was added.