Lithium Niobate Waveguide C-Axis Length DC Drift
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Solution Overview
Problem
Optical modulation components with optical waveguides made of lithium niobate (LN) films epitaxially grown on single crystal substrates suffer from significant DC drift, which affects the modulation waveform over time when a DC voltage is applied.
Innovation Solution
The electro-optical component incorporates an optical waveguide made of a lithium niobate film with a c-axis orientation, where the c-axis length is 13.88 Å or more, suppressing DC drift when a voltage is applied.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Volume of moving object
If an optical waveguide is made of an LN film epitaxially grown on a single crystal substrate, then the component size is significantly reduced, but DC drift occurs affecting modulation waveform stability
Solution Approach 1:
The patent changes the crystallographic parameter (c-axis length) of the lithium niobate film to 13.88 Å or more, which fundamentally alters the material's physical properties. This parameter change suppresses DC drift by modifying the electro-optic characteristics and reducing charge accumulation effects, thereby maintaining modulation waveform stability while preserving the miniaturized component structure
Solution Approach 2:
The patent applies a specific c-axis orientation (≥13.88 Å) to the lithium niobate film region, creating localized crystal quality enhancement. This local quality improvement in the waveguide active region suppresses DC drift without requiring changes to the entire component structure, enabling stable operation in the miniaturized device
2Reliability
If the c-axis length of the lithium niobate film is increased to 13.88 Å or more, then DC drift is suppressed, but the manufacturing precision requirement increases
Solution Approach 1:
The patent specifies that the c-axis length of 13.88 Å or more should be established during the epitaxial growth process itself, rather than attempting to adjust it afterward. This preliminary establishment of the critical parameter simplifies subsequent manufacturing steps and reduces the need for precise post-processing adjustments
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 reduces DC drift to 50% or less after one hour of DC voltage application, enhancing the reliability and miniaturization potential of electro-optical components.
Implementation Method 1
Lithium niobate (LiNbO3, hereinafter sometimes referred to as 'LN') has a large electro-optic constant and is therefore suitable as a material for electro-optical components
Implementation Method 2
an optical waveguide made of a dielectric thin film formed in contact with a main surface of the single crystal substrate, the dielectric thin film being made of a lithium niobate film that is an epitaxial film with a c-axis orientation
Data Source
AI summary
An electro-optical component includes: a single crystal substrate; an optical waveguide made of a dielectric thin film formed in contact with a main surface of the single crystal substrate; and an electrode configured to apply voltage to the optical waveguide, wherein the dielectric thin film is made of a lithium niobate film that is an epitaxial film with a c-axis orientation, and a c-axis length of the lithium niobate film is 13.88 Å or more.