Ferroelectric integrated optics: recent developments

Advances in rare-earth-doped waveguide lasers in LiNbO₃, waveguided second harmonic generation through quasi-phase-matching in LiNbO₃ and LiTaO₃, and pulsed laser epitaxial growth of LiNbO₃ on Sapphire are reported. Efficient lasers operating in CW, Q-switch, and mode-lock modes were fabricated in Nd:LiNbO₃. In order to assess the potential of bulk-doped Er:LiNbO₃ samples, spectroscopic measurements have been carried out, the main limiting mechanism identified, the corresponding up-conversion coefficient evaluated, and a comprehensive gain model developed. First lasing action in this material, when pumped at 1.48 μm, is described. Quasi-phase-matched generation of blue light with conversion efficiencies up to 150%/Wcm² is also demonstrated, and finally we present the fabrication of low-loss LiNbO₃ single-crystal waveguiding layers