Double-cantilever inverted cone spot-size conversion structure for waveguide coupling

Abstract

The invention discloses a double-cantilever inverted-cone spot-size conversion structure for waveguide coupling, and the structure consists of an input waveguide, a multimode waveguide interference region, two output waveguides, and parabolic inverted-cone structures at the rear ends of the output waveguides. The self-mapping effect is utilized to enable input light waves to generate a plurality of images on the cross section of the output waveguide, the light waves after beam splitting are spread in the output waveguide, and the cross section of the output waveguide passing through the parabola-shaped inverted cone structure is gradually reduced, so that the light waves of several output waveguides are diffused into the cladding so as to be conveniently coupled with a large-size waveguide. Compared with a traditional single inverted-cone-shaped coupler, the double-cantilever parabola-shaped inverted-cone-shaped structure is adopted, the alignment tolerance is improved, a small mode field of light transmitted by a small-size waveguide can be converted into a large mode field so that the light can be efficiently coupled into a large-size waveguide, meanwhile, a cladding layer where the parabola-shaped inverted-cone-shaped structure is located is suspended, substrate leakage is avoided, and the coupling efficiency is improved. And the loss during optical signal transmission is reduced.

Description

technical field [0001] The invention relates to the technical field of photon integration, in particular to a double cantilever inverted cone mode spot conversion structure for waveguide coupling. Background technique [0002] With the continuous acceleration of the global informatization process, the speed of optical communication continues to accelerate, and at the same time, the integration of devices becomes higher. Various discrete devices are unified on small-sized chips and coupled with optical fibers at the transmitting end and receiving end. [0003] However, waveguides of different materials, such as silicon waveguides, silicon nitride waveguides, silicon dioxide waveguides, and single-mode optical fibers, vary greatly in size. The width of silicon material waveguides is usually several hundred nanometers, and the width of silicon nitride material waveguides is about 2um. The input and output waveguide width of the silica arrayed waveguide grating is about 4um, whi...

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Problems solved by technology

[0006] Aiming at the technical problem that the alignment tolerance of the traditional inverted tapered waveguide coupler is small, and the light wave will leak from the cladding to the silicon substrate during the coupling process, resulting in low coupling efficiency, the present invention proposes an MMI (Multi-ModeInterference Multi-mode interference beam splitter) double cantilever inverted cone mode spot conversion structure, to achieve high-efficiency coupling of waveguides of different sizes under the condition of high alignment tolerance

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