Waveguide grating structure and preparation method thereof

Abstract

The invention discloses a waveguide grating structure and a preparation method thereof. The waveguide grating structure comprises: a waveguide; a covering layer arranged on the first surface of the waveguide and contacting the waveguide; and a diffraction structure arranged on the surface, away from the waveguide, of the covering layer and contacting the covering layer. According to the invention,when a light beam transmitted in a waveguide needs to be expanded, the light beam firstly passes through a covering layer and then is expanded to the space by a diffraction structure, so that the arranged covering layer can reduce the sensitivity of the diffraction structure to the light beam so as to increase the characteristic size of the diffraction structure, easily process the diffraction structure and reduce the requirement on the processing precision; due to the arrangement of the covering layer, the waveguide can be prevented from being etched when the diffraction structure is prepared through etching, so that the etching depth control difficulty is reduced, and the process feasibility and consistency are improved; and the diffraction intensity of the diffraction structure can bemodulated by adjusting the thickness of the covering layer, so that the length of the diffraction structure is effectively increased, and the beam divergence angle is reduced.

Description

technical field [0001] The invention relates to the field of photonic devices, in particular to a waveguide grating structure and a preparation method thereof. Background technique [0002] With the development of integrated optics, there are more and more fields of application of integrated optical chips. Beam expansion is an important functional requirement in integrated optical chips, and beam expansion is a basic functional requirement in integrated optical chips such as phased array chips, static array emission, switch array emission, and single-line emission. [0003] However, in traditional integrated optical chips, cylindrical lenses or off-chip diffraction structures are often used to expand the beam. These expansion methods make the chip bulky, require many packaging processes, and have low reliability. The existing integrated optical waveguide grating diffraction structure requires high processing precision and limited beam expansion capability. Contents of the...

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Problems solved by technology

[0004] In view of this, the embodiment of the present invention provides a waveguide grating structure and its preparation method to solve the technical problem in the prior art that the integrated optical waveguide grating diffraction structure requires high processing accuracy

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