High-average-power (> 20-W) Nd : YVO4 lasers mode locked by strain-compensated saturable Bragg reflectors

Strain-compensated double InGaAs quantum-well saturable Bragg reflectors (S BR's) with high damage thresholds have been developed for use as mode-locki ng elements in high-average-power neodymium lasers. Nd:YVO4 lasers have bee n developed with these new SBR's, which produce transform-limited pulses of 21-ps duration at 90 MHz and an average power of 20 W in a diffraction-lim ited output beam. The peak pulse power at an output power of 20 W was 10.6 kW. A comparison of the operating parameters of strained single and strain- compensated double-well SBR's indicates that the damage threshold increased by a factor of at least 2-3. Long cavity laser variants were investigated to assess the limitations of further power scaling. At a repetition frequen cy of 36-MHz stable mode-locked pulses with peak pulse powers of 24.4 kW an d pulse energies of 0.6 mu J could be generated. (C) 2000 Optical Society o f America [S0740-3224(00)02706-5].