Second-order optical non-linearity of proton exchanged lithium tantalate waveguides

• A detailed correlation between the fabrication conditions, crystallographic phase state of HxLi1-xTaO3 waveguides and second-order optical non-linearity has been investigated by using reflected SHG measurements from the polished waveguide end face. The non-linearity, strongly reduced after the initial proton exchange, is found to be restored and even increased after annealing. However, this apparent increase in the non-linearity is accompanied by a strong degradation of the quality of the SHG reflected beam in the region of the initial as-exchanged waveguide due to beam scattering. The high temperature proton exchange technique has been shown to produce high-quality alpha -phase waveguides with essentially undegraded non-linear optical properties. There is no phase transition when the alpha -phase waveguides are fabricated by direct exchange. This phase presents the same crystalline structure as that of LiTaO3 and maintains the excellent non-linear properties of the bulk material. The results obtained are important for the design fabrication and optimization of guided-wave non-linear optical devices in LiTaO3.

Nyckelord

refractive-index profiles

wave-guides

cut litao3

phases

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ref (ämneskategori)

art (ämneskategori)