Quasi-phase-matched parametric interactions in proton-exchanged lithium niobate waveguides

Analysis of High-Index Contrast Lithium Niobate Waveguides Fabricated by High Vacuum Proton Exchange

“…In order to see if the HiVacPE technique preserves the nonlinearity of the material, we performed surface Second Harmonic Generation (SHG) measurements. The experimental setup is similar to the one used in [13] and which is fully described in [28]. A laser beam at wavelength 1.5 µm is focused on the polished end facet of a waveguide and vertically scanned through the different regions: air, exchanged layers and substrate respectively.…”

Polarity inversion of GaN(0001) by a high Mg doping

“…This makes possible the compensation at regular intervals of the phase difference induced by the refractive index dispersion (for example, the index difference between the fundamental and second harmonic waves in the case of second harmonic generation). This smart approach has been proposed 40 years ago by Armstrong et al [2] and is nowadays commonly used in non-linear optics systems based on lithium niobate [3,4] or GaAs [5]. Recently, this technique has been successfully applied in GaN for second harmonic generation from a B1660 nm source [6].…”

Ultraviolet generation in periodically poled lithium tantalate waveguides

“…We employed a 400 Å radio-frequency sputtered SiO 2 mask and a melted mixture of benzoic acid and 3.6% lithium benzoate; this ratio was chosen in order to preserve the nonlinear optical properties and domain orientation in the crystal and yielded soft PE waveguides in the ␣-phase. 18 We performed PE at about 300°C for various times, up to 6 days. The silica mask was then removed and the planar waveguides formed on the +Z face were characterized at 632.8 nm by distributed ͑prism͒ coupling.…”