A kind of INOI-based optical waveguide reverse wedge mode spot coupler and its preparation method

Abstract

The invention discloses an LNOI-based optical waveguide reverse wedge-shaped mode spot coupler and a preparation method thereof. The LN layer on the top of the LNOI structure is used as the first waveguide core layer, and the first waveguide core layer is a reverse wedge-shaped structure; the first waveguide core layer The top is covered with a second waveguide core layer with a fixed width, and the refractive index of the second waveguide core layer is smaller than that of the first waveguide core layer. The invention utilizes the change of the height and width of the waveguide structure light transmission core layer to realize the expansion or compression of the incident light in the vertical and horizontal directions, and achieve the purpose of efficient coupling between the submicron-sized optical waveguide device and the optical chip or single-mode optical fiber The present invention can realize the direct end-face coupling of LNOI-based optical waveguide and optical chip or single-mode optical fiber, improve the mode spot matching degree of the two, and is beneficial to the integration of large-scale optical paths.

Description

technical field [0001] The invention relates to the technical field of optical interconnection and optical waveguide, in particular to an LNOI-based optical waveguide reverse wedge-shaped mode spot coupler and a preparation method thereof, which are used to realize the interconnection and coupling of an LNOI-based optical waveguide, an optical chip, and a common single-mode optical fiber. Background technique [0002] Lithium niobate crystal (LiNbO 3 , referred to as LN) is a negative uniaxial crystal with non-center symmetry and a wide wavelength transmission range, about 350nm~5500nm, with excellent piezoelectric, dielectric, ferroelectric, electro-optic, acousto-optic and Nonlinear optical performance, is the ferroelectric material with the best comprehensive index, and has the title of "optical silicon". The traditional lithium niobate body material is mature and has been widely used in modulators, fiber optic gyroscopes, fiber optic sensors and other fields. Lithium n...

AI Technical Summary

Problems solved by technology

Compared with silicon materials, lithium niobate materials, as artificial synthetic crystal materials, have stronger chemical resistance. The problem of micro-nano processing is a thorny problem that everyone is currently solving. The processing accuracy of silicon materials is relatively mature. There is a big gap, and it is still a challenge for the line width of hundreds of nanometers; therefore, for the inverted tapered waveguide coupling method of the SOI structure, in the LNOI structure, the characteristic size of the inverted tapered shape cannot achieve the best transmittance Size, no significant improvement for efficient coupling of optical waveguide devices to single-mode fibers or optical chips

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