Spot size converter

Abstract

The invention discloses a spot size converter. A Fresnel micro lens based on a metasurface structure is adopted, a first metasurface structure comprises a plurality of sub-wavelength grooves which are etched in a waveguide material and are the same in length and different in width, and a second metasurface structure comprises a plurality of sub-wavelength grooves which are etched in the waveguide material and are the same in length and width; the combined use of the two metasurface structures can reduce the size of the device, and also avoids the step of etching the extremely small line width, thereby reducing the technological requirements. The mode field width of single-mode input light can be changed under the condition that the mode order of the single-mode input light is maintained. A wide-spot fundamental mode beam can be changed into a cylindrical wave to realize a beam bunching function, or the cylindrical wave can be changed into a wide-spot fundamental mode beam to realize a beam expanding function. The mode field of the wide-spot fundamental mode can be widened by increasing the period number of the Fresnel micro lens, and the actual requirements of various application scenes can be met. The spot size converter can realize the functions of a beam splitter, a collimator and the like, and is suitable for different application scenes.

Description

technical field [0001] The invention belongs to the field of integrated optics, and more specifically relates to a mode spot converter. Background technique [0002] The mode spot converter is mainly used to match optical devices with different mode spot sizes. It can change the mode spot size while maintaining the mode spot characteristics in a small space, so as to achieve low-loss coupling between waveguides with different widths. It is widely used in the field of optics. [0003] At present, there are two main ideas for designing the mode spot converter. The first one is to change the shape of the waveguide along the propagation direction of the light field, so that the mode coupling of the light field occurs under different boundary conditions, so as to obtain mode spots of different widths. One purpose requires the use of various complex algorithms, such as genetic algorithm, particle swarm algorithm, step-by-step iterative feedback analysis algorithm, etc. These algo...

AI Technical Summary

Problems solved by technology

[0004] Aiming at the above defects or improvement needs of the prior art, the present invention provides a speckle converter, thereby solving the technical problems of the existing speckle converter such as complex design and manufacture, narrow applicability, and small beam expansion and focusing width.

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