Compact on-chip polarization splitter-rotator based on Bezier curve graded index waveguide

Abstract

The invention discloses a compact on-chip polarization splitter-rotator based on a Bezier curve graded index waveguide. The Bezier curve graded index waveguide structure is based on a standard SOI wafer structure and comprises a substrate with an oxide (SiO2) buried in the bottom layer, silicon waveguides are arranged on the substrate, and the silicon waveguides comprise a common output waveguide and a special structure waveguide containing a Bezier curve boundary. The common waveguide structure is composed of a cuboid waveguide. The special structure waveguide is composed of an input waveguide, an output waveguide, a width gradually-changing waveguide (a Bezier curve gradually-changing structure) and a coupling area, the width of the gradually-changing waveguide is determined by a third-order Bezier curve, and the coupling area is composed of two asymmetric waveguide areas. Polarization beam splitting rotation of two kinds of input polarized light TE0 and TM0 is achieved in a wide working wave band, the insertion loss is low, the polarization conversion efficiency is high, the crosstalk is low, and compared with similar devices, the compact on-chip polarization splitter-rotator is optimal.

Description

technical field [0001] The invention relates to the technical field of optical fiber communication, in particular to an on-chip polarization rotating beam splitter. Background technique [0002] Photonic Integrated Circuits (PIC) based on silicon-on-insulator (SOI) platform have developed rapidly in recent years. In addition to its large-scale, high-density, high-bandwidth, and low-power characteristics, the main reason is that it is compatible with a complementary metal oxide semiconductor (ComplementaryMetalOxideSemiconductor, CMOS) manufacturing process. However, due to the characteristics of the CMOS process and the material itself, SOI devices have high birefringence, so that different polarization modes produce different responses in the loop, and the resulting polarization mode dispersion and loss will greatly degrade system performance. Single-mode silicon nanophotonic waveguides typically have birefringence as high as ~0.7, resulting in silicon photonic devices tha...

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Problems solved by technology

TM based on tapered or tapered-ridge waveguides during the design process 0 -TE 1 Mode converters have high requirements on the slope of the waveguide gradient, which usually needs to be low enough to achieve efficient coupling of modes and complete transfer of energy, which also means that the side slope of this type of tapered or tapered ridge waveguide is relatively low. Small, the corresponding waveguide length is longer, occupying more area

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