Micro-ring resonator polarization insensitivity via gradient waveguide
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Solution Overview
Problem
Micro-ring resonators in optical communications exhibit strong polarization correlation, limiting their ability to operate with the same wavelengths for transverse electric (TE) and transverse magnetic (TM) polarized light, which is necessary for polarization-insensitive optical components, and require multiple components, increasing complexity and power consumption.
Innovation Solution
A micro-ring resonator design that uses a common waveguide and two polarization splitters to ensure consistent operating wavelengths for TE and TM paths, reducing the distance between micro-rings and minimizing polarization interference, allowing for a single set of components and reduced power consumption.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Volume of moving object
If conventional discrete optical components are replaced with integrated waveguide components having high refractive index difference, then miniaturization is achieved, but strong polarization correlation occurs causing different operating wavelengths for TE and TM modes
Solution Approach 1:
The micro-ring resonator is divided into multiple waveguide segments with different cross-sectional areas. Specifically, the ring waveguide includes first, second, third, and fourth waveguide portions with progressively larger cross-sectional areas, creating a gradient structure that differentially affects TE and TM modes to compensate for polarization-dependent wavelength shifts
Solution Approach 2:
Different portions of the micro-ring resonator are assigned different local properties through varying cross-sectional areas. The waveguide cross-section changes along the ring perimeter, with each portion having optimized dimensions to provide local polarization compensation, achieving overall polarization insensitivity while maintaining miniaturization
2Ease of operation
If two sets of micro-ring resonators with different radii are used to process TE and TM light separately, then polarization separation is achieved, but device complexity and power consumption are doubled
Solution Approach 1:
The patent merges the functions of separate TE and TM processing paths into a single micro-ring resonator structure. By integrating polarization compensation directly into the ring waveguide through cross-sectional area variation, the design eliminates the need for separate micro-rings for different polarizations, reducing component count while maintaining polarization processing capability
Solution Approach 2:
The single micro-ring resonator is designed to handle both TE and TM polarized light simultaneously through its gradient cross-sectional structure. The waveguide portions with varying cross-sectional areas provide universal polarization compensation for both modes within one device, replacing the need for multiple specialized components
3Object-affected harmful factors
If minimum distance between micro-rings is increased to prevent coupling, then polarization interference is reduced, but available space for dense wavelength multiplexing is limited
Solution Approach 1:
The patent extracts the polarization compensation function from a separate component and integrates it directly into the micro-ring resonator waveguide structure. By incorporating gradient cross-sectional areas within the ring itself, the design eliminates the need for additional polarization compensation components that would occupy extra space, enabling denser wavelength multiplexing while maintaining polarization insensitivity
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
The solution achieves polarization insensitivity by ensuring consistent operating wavelengths for TE and TM paths, reducing the complexity and power consumption of optical components, and enabling dense wavelength multiplexing applications.
Implementation Method 1
input light in an unknown polarization state is split by a polarization splitter (Polarization Splitter, PS) into TE light and TM light
Implementation Method 2
a method for reducing the sizes of the optical components is mainly to replace conventional discrete optical components with integrated waveguide components having a high refractive index difference
Implementation Method 3
it is required that operating wavelengths of the two micro-rings should be the same
Data Source
Figure 1~2
Figure 3~4
Figure 5A
AI summary
A micro-ring resonator includes: at least one first straight waveguide; a second waveguide (Arm3) and a third waveguide (Arm2), where the second waveguide (Arm3) and the third waveguide (Arm2) form a closed annular waveguide, and the annular waveguide is coupled to the first waveguide; a fourth waveguide (Arm1), where the fourth waveguide (Arm1) is coupled to the annular waveguide; and a polarization splitter (PS), where one end of the polarization splitter (PS) is connected to the fourth waveguide (Arm1), and one end is connected to the second waveguide (Arm3) in the annular waveguide. In the micro-ring resonator, a distance between two waveguides for separately transmitting different polarized light breaks a limitation of a resonator radius, and further, a distance between a TE path and a TM path is reduced.