Amorphous Core Optical Waveguide Crosstalk Suppression
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Solution Overview
Problem
Optical modulators face a trade-off between suppressing crosstalk and maintaining modulating efficiency and coupling efficiency, as reducing the thickness of optical waveguides to prevent crosstalk weakens light confinement and deteriorates transmission characteristics.
Innovation Solution
The optical device incorporates an electro-optic crystal layer with first optical waveguides in a non-amorphous state and a second optical waveguide in an amorphous state, connected to the first waveguide, to suppress crosstalk by eliminating the coincidence of effective refractive indices in TE and TM modes, thereby improving modulating and coupling efficiencies.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-generated harmful factors
If the thickness of optical waveguides is reduced to suppress crosstalk, then crosstalk is suppressed, but light confinement is weakened and transmission characteristics deteriorate
Solution Approach 1:
The patent applies different material states to different regions of the optical waveguide structure. Specifically, the core layer is formed in an amorphous state while the cladding layer maintains a crystalline state. This local differentiation allows the core to have uniform refractive index properties that suppress crosstalk, while the crystalline cladding provides strong light confinement, thereby resolving the contradiction between crosstalk suppression and transmission characteristic maintenance.
Solution Approach 2:
The patent changes the physical state parameter of the optical waveguide core from crystalline to amorphous. This parameter change fundamentally alters the refractive index characteristics of the core material, eliminating the coincidence of effective refractive indices between TE and TM modes. This enables crosstalk suppression without requiring reduction of waveguide thickness, thus maintaining strong light confinement and good transmission characteristics.
2Object-generated harmful factors
If the thickness of optical waveguides is reduced to prevent crosstalk, then crosstalk is suppressed, but modulating efficiency deteriorates
Solution Approach 1:
By forming only the core layer in an amorphous state while keeping the cladding layer crystalline, the patent creates local quality differences that enable the core to suppress crosstalk through uniform refractive index distribution, while the crystalline cladding maintains strong optical confinement. This allows the use of thicker waveguides that preserve modulating efficiency without suffering from crosstalk issues.
Solution Approach 2:
The patent changes the state parameter of the core material to amorphous, which fundamentally alters its optical properties. This parameter change eliminates the refractive index coincidence problem between polarization modes, suppressing crosstalk. The thicker waveguide structure enabled by this change actually improves modulating efficiency by providing better overlap between the optical mode and the electro-optic interaction region.
3Object-generated harmful factors
If the thickness of optical waveguides is reduced to prevent crosstalk, then crosstalk is suppressed, but coupling efficiency deteriorates
Solution Approach 1:
The patent creates local quality differentiation by amorphizing only the core layer while maintaining the crystalline structure of the cladding layer. This allows the core to provide uniform refractive index for crosstalk suppression, while the crystalline cladding ensures strong optical confinement and good mode matching with optical fibers, thereby maintaining high coupling efficiency without requiring thin waveguide structures.
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
This configuration effectively suppresses crosstalk while maintaining high modulating and coupling efficiencies, even with thicker waveguides, by ensuring no propagation angle intersects the refractive indices of signal and unnecessary light modes, enhancing overall performance.
Implementation Method 1
When a voltage is applied to the signal electrode, an electric field is generated in the optical waveguide in a direction perpendicular to the surface of the optical modulator. The electric field changes a refractive index of the optical waveguide, resulting in a change in phase of light propagating through the optical waveguide
Data Source
AI summary
An optical device includes an electro-optic crystal layer, a first optical waveguide formed in the electro-optic crystal layer, and an electrode that applies an electric signal to the first optical waveguide. Further, the optical device includes a second optical waveguide in an amorphous state formed in the electro-optic crystal layer and connected to the first optical waveguide.