A silicon-based optical waveguide polarization converter and its preparation method

Abstract

The invention discloses a silicon-based optical waveguide polarization converter, which comprises a silicon substrate, a silicon dioxide layer covering the upper surface of the silicon substrate, a silicon waveguide layer and a metal strip layer, wherein the silicon waveguide layer has a cross section of "L" shape, the lower surface of which is grown or bonded on the upper surface of the silicon dioxide layer, the upper surface forms a high mesa and a low mesa, and the metal strip layer covers the low mesa of the silicon waveguide layer. By integrating metal strips in the low mesa of the asymmetric silicon waveguide layer, surface plasmon waves are formed in the silicon waveguide layer, which increases the effective refractive index difference between the two polarization modes, because the efficiency of polarization conversion is different from the mode effective refractive index difference Inversely proportional to, thereby greatly reducing the length of the polarization converter. In addition, the metal strip layer of the present invention is prepared on the low mesa of the asymmetric silicon waveguide, so it can be directly obtained through the metal evaporation and lift-off process after the etching process of the low mesa, without additional alignment photolithography process, so it is easy to preparation.

Description

technical field [0001] The invention relates to a silicon-based optical waveguide polarization converter and a preparation method thereof, in particular to a silicon-based optical waveguide polarization converter using surface plasmon waves to improve polarization conversion efficiency and a preparation method thereof, belonging to the technical field of optical communication. Background technique [0002] Optical communication is a communication technology with light waves as the carrier. Compared with cables and radios, optical communication has a huge communication bandwidth, and it has an irreplaceable position in today's multimedia and big data era. Optical fiber is the carrier of long-distance optical information transmission, and the processing of optical signals is mostly completed by various optical modules or optoelectronic chips. In order to further improve the integration of optoelectronic chips, silicon-based optical waveguide devices with high refractive index ...

AI Technical Summary

Problems solved by technology

This technology relies on the coupling of two modes in an asymmetric optical waveguide to form a polarization conversion. However, the effective refractive index difference between the two coupled modes in an ordinary silicon-based optical waveguide polarization converter is too small, resulting in the need for an asymmetrical waveguide of about 100 microns. Symmetrical waveguides can achieve sufficient polarization conversion, which is not conducive to the high integration of optoelectronic device chips

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