| Active integrated optics devices were fabricated in thin-film lithium niobate, using ion-implantation induces exfoliation of the surface layer off the devices realized in bulk crystal wafers. Devices examined were optical beam scanner and spectrally tunable second harmonic generation PPLN device. Both devices utilize electrooptic effect, which causes material refractive index change proportional to applied voltage to the device and inversely proportional to the device substrate thickness. More than ten-fold reduction in driving voltage was obtained in thin-film devices, compared to corresponding devices in bulk. Namely, deflection angles of +/-1° were obtained in a 3mm long 10mum thick lithium niobate crystal with voltages of +/-150V, whereas for a corresponding deflection angle in bulk, voltages on the order of 2-4kV are needed. Also, electrooptic tunability of the QPM second harmonic generation PPLN device in thin film was demonstrated, with the ability to tune the second harmonic output out of a modelocked fiber laser by up to twice the FWHM of the second harmonic linewidth, using voltages of +/-150V. Again, comparable performance in bulk requires voltages in the kilovolt range. This demonstrated feature of the thin-film electrooptically tunable structures may lead to a new generation of integrable, low-voltage/power active devices for integrated optics applications. |
