Lithium niobate optical waveguide device and preparation method thereof

Abstract

The invention relates to a preparation method of a lithium niobate optical waveguide device, and belongs to the technical field of optical communication. According to the invention, a new cladding structure is introduced, a micron-order lithium niobate thin film optical waveguide device is obtained through the processes of ion implantation, BCB spin coating, bonding, annealing and the like, the preparation of a ridge waveguide is facilitated in process, the transmission loss of a finally prepared optical waveguide is effectively reduced, and the constraint of light is increased. According to the invention, a BCB is selected as a bonding medium material and used as an adhesive at normal temperature, so that a lithium niobate film and a substrate can be effectively combined together, the BCBis cured after annealing and used as a waveguide cladding, the subsequent mask etching process of a lithium niobate thin film is simple and convenient, and the lithium niobate thin film is not damaged; the optical refractive index of lithium niobate is 2.2, is greater than the refractive index 1.5 of the BCB and is greater than the refractive index 1 of air, and light can be well restrained in the waveguide, so that excellent performance can be realized without proton exchange.

Description

technical field [0001] The invention relates to a lithium niobate optical waveguide device and a preparation method thereof, belonging to the technical field of optical communication. Background technique [0002] Lithium niobate crystal has excellent electro-optic, acousto-optic and nonlinear properties, and the material has stable chemical properties. It is the most commonly used inorganic dielectric crystal material for integrated optics and is widely used in the preparation of various optical waveguide devices in the field of optical communication. By changing the structure of lithium niobate optical waveguides and electrodes, a variety of optical transmission and control devices can be prepared, such as optical waveguides, electro-optical modulators, and microring resonators. [0003] In order to make a waveguide, it is necessary to fabricate SiO on the upper surface of the substrate 2 or Si 3 N 4 thin film, and then etched the mask window by photolithography technol...

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Problems solved by technology

[0005] In practical applications, due to the thickness of the substrate, the light will dissipate to the surroundings, thereby increasing the transmission loss, so it is necessary to thin the various tangential lithium niobate blocks. The current method is to mechanically reduce the thickness of the substrate. grinding, but the thickness of lithium niobate obtained by this method is still tens of microns, which cannot effectively reduce the loss; secondly, the ion exchange process is complicated and cannot be applied to all tangential lithium niobate, and the refraction of the upper and lower layers The rate difference is small and does not tie the beam well in the waveguide

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