Grating coupler and optical chip

By designing a reflective grating structure and transmission grating structure in the grating coupler and setting corresponding grating units, the problem of low coupling efficiency of existing fiber couplers is solved, and higher directionality and coupling efficiency are achieved.

CN119717131AActive Publication Date: 2025-03-28SUZHOU DAWNING SEMI TECH CO LTD
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Patent Information

Application Number
CN202510239776.7
Authority / Receiving Office
CN · China
Patent Type
Applications(China)
Current Assignee / Owner
Filing Date
2025-03-03
Publication Date
2025-03-28
Estimated Expiration
2045-03-03

AI Technical Summary

Technical Problem

The coupling efficiency of existing fiber couplers is not high, mainly due to the serious mismatch between the optical fiber mode field and the optical waveguide mode field, resulting in large losses in the optical signal during the coupling process.

Method used

A grating coupler is designed, including a reflective grating structure and a transmission grating structure. By providing at least a part of the first grating unit and the second grating unit, the etching of the transmission grating structure is ensured to be cleaner, thereby improving directionality and coupling efficiency. At the same time, the light utilization rate is increased by stacking the reflected grating structure and the transmission grating structure.

Benefits of technology

The directionality and coupling efficiency of the grating coupler are improved. Compared with the single-layer silicon nitride grating coupler, the peak coupling efficiency is improved by 37%, with a 1dB bandwidth of 40nm and a 3dB bandwidth of nearly 100nm.

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Abstract

The invention relates to the technical field of grating couplers, in particular to a grating coupler and an optical chip. The grating coupler includes: a substrate; the reflection grating structure is located on one side of the substrate, and the reflection grating structure comprises a plurality of first grating units which are arranged at intervals; the transmission grating structure is located on the side, away from the substrate, of the reflection grating structure, the transmission grating structure comprises a plurality of second grating units arranged at intervals, and at least part of the first grating units and the second grating units are correspondingly arranged. According to the grating coupler, at least part of the first grating units and the second grating units are correspondingly arranged, so that when the transmission grating structure is formed, no residue exists between the adjacent second grating units, the second grating units are etched cleanly, and the directivity and the coupling efficiency of the grating coupler are improved. Specifically, the orthographic projection of at least part of the first grating units on the substrate can be arranged in the orthographic projection of the second grating units on the substrate.
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