Electro-optic modulator electrode interface for velocity matching
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Solution Overview
Problem
High-speed electro-optic modulators face limitations in bandwidth due to the mismatch in propagation velocities between optical and RF signals, leading to reduced modulation efficiency and bandwidth, particularly in LiNbO3 materials, where the high relative permittivity results in slower RF signal propagation and phase mismatch.
Innovation Solution
The introduction of defective or amorphous crystal structures under electrodes in electro-optic modulators, achieved through selective ion implantation, reduces the relative permittivity and matches the propagation velocities of optical and RF signals, enabling high-bandwidth modulation without compromising structural integrity or increasing optical losses.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If LiNbO3 material is used for electro-optic modulation, then electro-optic modulation efficiency is improved, but RF signal propagation speed decreases due to high relative permittivity
Solution Approach 1:
The patent applies local quality by creating distinct regions with different crystal structures: the optical waveguide region maintains a crystalline structure for high electro-optic modulation efficiency, while the electrode interface region introduces defects or amorphous structure to reduce relative permittivity and increase RF propagation speed. This spatial differentiation allows each region to optimize for its specific function.
Solution Approach 2:
The patent changes the physical and chemical parameters of the material by introducing defects or amorphous structure in the electrode interface region, which alters the relative permittivity parameter. This parameter change enables better velocity matching between optical and RF signals while maintaining the electro-optic modulation performance.
2Productivity
If RF modulating signal and laser signal are co-propagated along the modulator, then modulation bandwidth is increased, but phase mismatch occurs due to different propagation velocities
Solution Approach 1:
The patent introduces defects or amorphous structure specifically in the electrode interface region to locally change the refractive index and permittivity, thereby adjusting the RF propagation velocity to match the optical signal velocity and maintain phase coherence during co-propagation.
Solution Approach 2:
The defective crystal structure or amorphous structure in the electrode interface region acts as an intermediary that mediates between the optical and RF propagation requirements, enabling velocity matching without compromising either signal's integrity.
3Power
If high relative permittivity material is used, then electro-optic effect is enhanced, but RF field propagation becomes slower and out of phase with optical signal
Solution Approach 1:
The patent maintains high relative permittivity in the optical waveguide region for strong electro-optic effect while introducing defects or amorphous structure in the electrode interface region to reduce permittivity and increase RF propagation speed, allowing both requirements to be satisfied simultaneously in different locations.
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 approach allows for efficient operation with bandwidths exceeding 100 GHz, maintaining low optical loss and RF impedance matching, thereby enhancing modulation efficiency and extending the modulator's bandwidth limits.
Implementation Method 1
The introduction of defective or amorphous crystal structures under electrodes in electro-optic modulators, achieved through selective ion implantation, reduces the relative permittivity and matches the propagation velocities of optical and RF signals
Implementation Method 2
High-speed optical data communication links often use electro-optic modulators that operate based on an electro-optical effect in which an optical characteristic, such as dielectric constant, is electrically controlled. For example, a modulator based on LiNbO3 can apply a RF modulating signal to vary the optical refractive index for a laser signal propagating along an optical waveguide of the modulator
Implementation Method 3
The introduction of defective or amorphous crystal structures under electrodes in electro-optic modulators, achieved through selective ion implantation
Data Source
AI summary
An electro-optic modulator device includes a first optical waveguide region of a substrate and a second optical waveguide region of the substrate. The first optical waveguide region and the second optical waveguide region have crystalline structures. The electro-optic modulator device also includes a first electrode interface region of the substrate on a first side of the first optical waveguide region, a second electrode interface region of the substrate on a second side of the first optical waveguide region and on a first side of the second optical waveguide region, and a third electrode interface region on a second side of the second optical waveguide region. Each of the first electrode interface region, the second electrode interface region, and the third electrode interface region include material having a defective crystal structure or an amorphous structure.