Embedded Optical Waveguide Groove for Polarization-Independent Low Loss
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Solution Overview
Problem
Existing optical waveguides suffer from optical loss and polarization dependence due to the need for a groove to insert a wavelength plate, which causes light emission and is an unavoidable challenge.
Innovation Solution
An embedded optical waveguide with a groove formed on one side of the core, featuring a refractive index distribution where the principal axis of birefringence is rotated by forming the groove to eliminate polarization dependence without the need for a separate wavelength plate.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If a groove is formed to insert a wavelength plate to eliminate polarization dependence, then polarization dependence is eliminated, but optical loss increases due to light emission in the groove
Solution Approach 1:
The patent extracts the wavelength plate from the system by eliminating the need for a separate groove structure. Instead of inserting a wavelength plate into a groove, the polarization control function is integrated directly into the waveguide core through controlled stress distribution and refractive index manipulation, thereby eliminating the source of optical loss while maintaining polarization independence
Solution Approach 2:
The patent merges the polarization control function with the waveguide structure itself. By forming a groove on one side of the core that creates asymmetric stress distribution, the waveguide simultaneously guides light and controls polarization states, eliminating the need for separate wavelength plate components and their associated loss
2Adaptability or versatility
If a groove is formed for inserting wavelength plate, then polarization state control is achieved, but device complexity increases
Solution Approach 1:
The patent combines the groove structure with the waveguide core into a single integrated structure. The groove is formed directly on the core during fabrication, creating a unified component that performs both light guidance and polarization control functions, thereby reducing device complexity compared to separate groove and wavelength plate structures
Solution Approach 2:
The waveguide structure with the asymmetric groove serves multiple functions simultaneously: it guides light propagation, controls polarization states through stress-induced refractive index changes, and eliminates the need for separate polarization control components, thereby reducing overall device complexity
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 optical waveguide suppresses light loss and propagates light with high efficiency by eliminating polarization dependence through controlled stress distribution and refractive index manipulation.
Implementation Method 1
controlled stress distribution and refractive index manipulation
Implementation Method 2
an optical waveguide element such as a Mach-Zehnder interferometer has polarization dependence caused by birefringence
Implementation Method 3
a refractive index distribution in a plane perpendicular to the light propagation direction is a distribution in which a principal axis of a refractive index ellipse is rotated by a rotation angle
Data Source
AI summary
Provided is an optical waveguide capable of suppressing optical loss in a groove portion into which a wavelength plate is inserted while eliminating polarization dependence. An optical waveguide according to the present disclosure is an embedded optical waveguide formed on a substrate, including a lower cladding; a core; an upper cladding; and a groove formed on one side of a side surface of the core with respect to a light propagation direction and extending in a direction parallel to the core, wherein a refractive index distribution in a plane perpendicular to the light propagation direction is a distribution in which a principal axis of a refractive index ellipse has a rotation amount with respect to a horizontal direction of the substrate.