Lithium niobate optical waveguide and method for preparing near-stoichiometric lithium niobate optical waveguide by means of titanium diffusion and vapor transport equilibration (VTE)

Abstract

The invention relates to the technical field of optical devices and especially relates to a lithium niobate optical waveguide and a method for preparing the near-stoichiometric lithium niobate optical waveguide by means of titanium diffusion and VTE. The lithium niobate optical waveguide comprises a substrate and a waveguide layer arranged on the substrate. The substrate is made of a lithium niobate crystal. The waveguide layer is arranged on a +z surface of the lithium niobate crystal, the direction of a stripe waveguide is the y direction of the lithium niobate crystal. A photo-etching process is adopted for preparing the waveguide layer on the substrate. The prepared optical waveguide is good in performance, is low in loss and has a good effect on various kinds of optical researches; in addition, the lithium niobate crystal after the titanium diffusion process is subjected to a lithium-rich vapor transport equilibration process, and a near stoichiometric ratio (NS, [Li]/[Nb]>99%) is achieved. The near-stoichiometric lithium niobate crystal has more excellent advantages that the crystal defects are less, the optical uniformity is good, and higher electro-optic and non-linear effects are realized. The titanium diffusion optical waveguide has the advantages that the waveguide performance is good, the loss is relatively low, etc.

Description

technical field [0001] The invention relates to the technical field of optoelectronic devices, in particular to a lithium niobate optical waveguide and a method for preparing a near-stoichiometric ratio lithium niobate optical waveguide through titanium diffusion and VTE. Background technique [0002] A waveguide is a structure used to guide electromagnetic waves in a direction. Common waveguide structures mainly include parallel twin wires, coaxial lines, parallel slab waveguides, rectangular waveguides, circular waveguides, microstrip lines, slab dielectric optical waveguides, and optical fibers. From the perspective of guiding electromagnetic waves, they can be divided into inner and outer regions, and electromagnetic waves are limited to propagate in the inner region (requiring the transverse resonance principle to be satisfied within the waveguide cross section). [0003] Generally, waveguides refer to hollow metal waveguides and surface waveguides of various shapes. T...

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