Structure for improving the coupling efficiency between submicron silicon waveguide and common single-mode fiber

Abstract

The invention discloses a structure for improving the coupling efficiency between a submicron silicon waveguide and a common single-mode fiber. In the structure, the substrate material for making a submicron silicon waveguide is a silicon wafer on an insulating substrate, and the silicon wafer includes three layers of materials from bottom to top: substrate silicon, a buried oxide layer and top silicon, wherein the buried oxide layer is doped silicon dioxide; after forming a submicron silicon waveguide on the top silicon of the wafer through photoetching and etching, the doped silicon dioxide in the first layer is deposited on the silicon waveguide and fully covers the silicon waveguide; and after the doped silicon dioxide in the layer is photoetched and etched, the doped silicon dioxide in the second layer is deposited on the silicon waveguide. Therefore, the formed silicon dioxide waveguide is used as a connection channel for a common single-mode fiber, so that the mode field mismatch loss and the reflection loss during the coupling process of the submicron silicon waveguide and the common single-mode fiber, and the coupling efficiency between the submicron silicon waveguide and the common single-mode fiber can be improved.

Description

technical field [0001] The invention relates to the technical field of optical fiber communication and integrated optics, in particular to a structure for improving the coupling efficiency of a submicron silicon waveguide and a common single-mode optical fiber. Background technique [0002] Due to the large bending radius of traditional silicon-based large-section waveguides (on the order of hundreds of microns to millimeters), it is difficult to integrate multiple optical functional devices on a single chip, which limits the development of large-scale integrated optical circuits. With the advancement of semiconductor planar processing technology, silicon waveguides with sub-micron cross-sectional dimensions began to appear, and their radii can be as small as several microns without significant loss. Submicron silicon waveguides have attracted widespread attention because of their potential high-integration characteristics. [0003] Since the cross-sectional area of ​​the s...

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Problems solved by technology

The coupling loss of direct butt coupling between the two is above 10dB, which is unacceptable in practical applications

However, this approach can only increase the mode field of the silicon waveguide to a limited extent, and it is still necessary to use a tapered fiber with a small mode field to couple with the waveguide inverted cone structure. The cost is high and the coupling tolerance is small, so it is difficult to be used in the packaging of actual devices.

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