Plasmonic Slot Waveguide Modulator Using Amorphous Silicon Pockels Effect
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Solution Overview
Problem
Existing electro-optic devices face limitations such as limited speed, high inherent losses, large footprint, and high driving voltages, particularly in silicon-based modulators, and the use of polymers with poor reliability.
Innovation Solution
Employing amorphous silicon as a dielectric material in a metal-dielectric-metal slot waveguide structure to induce an electric-field-induced Pockels effect, leveraging its high third-order nonlinear susceptibility to achieve effective second-order nonlinear susceptibility, compatible with standard manufacturing processes and avoiding polymer reliability issues.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If plasma dispersion based silicon optical modulators are used, then the device can be manufactured with standard processes, but the speed is limited to 50GHz
Solution Approach 1:
The patent changes the fundamental physical mechanism from plasma dispersion to Pockels effect by using electric field induced second-order nonlinear optical effects in silicon waveguides. This parameter change enables ultra-fast modulation speeds exceeding 50GHz while maintaining compatibility with standard silicon manufacturing processes
Solution Approach 2:
The patent replaces the plasma dispersion mechanism (which relies on carrier concentration changes) with an electric field induced optical effect (Pockels effect). This substitution eliminates the speed limitation imposed by carrier recombination and mobility, achieving ultra-fast modulation without sacrificing manufacturability
2Area of stationary object
If ring resonators are used to reduce footprint, then the device size is reduced, but the operating wavelength is limited to single wavelength and requires power-hungry thermo-optical tuning
Solution Approach 1:
The patent extracts the wavelength tuning function from the modulation mechanism itself. By using Pockels effect-based phase modulation that is inherently broadband, the device eliminates the need for thermo-optical tuning mechanisms, thereby removing the associated power consumption while maintaining compact footprint
Solution Approach 2:
The patent creates a universal modulator that operates across multiple wavelengths without requiring wavelength-specific tuning. The electric field induced Pockels effect provides broadband operation, making the device multi-functional across different telecom wavelengths without additional power-hungry tuning components
3Speed
If polymers with high χ(2) are used for Pockels effect modulation, then ultra-fast modulation is achieved, but the reliability is poor due to degradation at high temperatures
Solution Approach 1:
The patent copies the desirable Pockels effect behavior from polymers into silicon waveguides through electric field induced second-order nonlinear optical effects. This copying approach achieves the ultra-fast modulation speed of polymer-based devices while maintaining the thermal stability and reliability of inorganic silicon materials
Solution Approach 2:
The patent effectively creates a composite optical system where the silicon waveguide structure provides thermal stability and the electric field induced nonlinear optical effects provide ultra-fast modulation capability. This composite approach combines the advantages of both polymer-based Pockels effect and silicon thermal stability
4Ease of manufacture
If crystalline silicon waveguides are used for Pockels effect, then the device can be manufactured with standard processes, but the symmetry inhibits second-order optical nonlinear susceptibility
Solution Approach 1:
The patent introduces dynamic control of the optical nonlinear susceptibility through applied electric fields. By using the Pockels effect, the device dynamically induces second-order nonlinear susceptibility in silicon waveguides that would otherwise be forbidden by symmetry, enabling efficient modulation while maintaining standard manufacturing processes
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 provides ultra-fast, compact, and linear modulation with low power consumption, suitable for telecom and datacom applications, and microwave photonics, including quantum technologies, by utilizing amorphous silicon's high χ(3) and reduced plasma dispersion effects.
Implementation Method 1
The device is configured to electrically control the phase of a propagating light signal through electric-field induced Pockels effect
Implementation Method 2
leveraging its high third-order nonlinear susceptibility to achieve effective second-order nonlinear susceptibility
Data Source
Figure 1a
Figure 1b
Figure 2
AI summary
According to an example aspect of the present invention, there is provided an electro-optic plasmonic device (1) comprising: a slot waveguide (6) that is defined by a first metallic electrode (2), a second metallic electrode (3) and 5 dielectric material (4) in a slot between the first and second metallic electrodes. The device (1) is configured to utilize the electric field induced Pockels effect.