BTO-Clad SiN Phase Modulators With Low-Loss Dielectric Gap
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Solution Overview
Problem
Existing silicon photonic phase modulators face challenges in integrating with silicon nitride waveguides for visible light applications, requiring transparency, low-loss, low-luminescence, and compatibility with CMOS processes, while maintaining ultra-low power dissipation and efficient phase modulation.
Innovation Solution
A BTO membrane is used as a cladding for SiN waveguides, separated by a sub-wavelength gap with a dielectric material, allowing low-loss phase modulation through voltage-controlled refractive index changes, and integrated with Mach-Zehnder interferometers for network switching.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Power
If a BTO membrane is used as cladding for SiN waveguides, then phase modulation efficiency is improved, but propagation loss increases due to material absorption
Solution Approach 1:
The device is divided into distinct functional sections: an input waveguide section without BTO cladding (low loss), a modulation section with BTO cladding (high efficiency), and an output waveguide section without BTO cladding (low loss). This segmentation allows the optical signal to experience low loss during propagation while achieving efficient phase modulation only in the designated modulation region.
Solution Approach 2:
A dielectric layer is introduced as an intermediary between the SiN waveguide and the BTO membrane. This dielectric layer acts as a separator that prevents direct optical interaction between the waveguide mode and the BTO material, thereby reducing absorption losses while still allowing the BTO membrane to exert its electro-optic influence on the waveguide for phase modulation.
2Power
If the BTO membrane is placed close to the waveguide for efficient modulation, then modulation efficiency is improved, but coupling loss increases
Solution Approach 1:
The dielectric layer serves as a mediator that enables close proximity coupling between the BTO membrane and the SiN waveguide while preventing direct optical coupling losses. This intermediate layer allows the electric field from the BTO to effectively modulate the waveguide mode without causing excessive absorption or scattering losses that would occur with direct contact.
Solution Approach 2:
The thickness of the dielectric layer is optimized to achieve the right balance between modulation efficiency and coupling loss. By precisely controlling this parameter, the design achieves sufficient electric field interaction for efficient modulation while maintaining low optical loss through the interface between the BTO membrane and waveguide.
3Adaptability or versatility
If visible light wavelength is used for quantum computing applications, then application suitability is improved, but material transparency requirements become more stringent
Solution Approach 1:
The device employs a composite structure combining SiN waveguides with BTO membrane cladding. This composite material approach leverages the transparency and low loss properties of SiN in the visible range while adding the electro-optic modulation capability of BTO, achieving both visible light compatibility and efficient modulation.
Solution Approach 2:
The optical path is segmented into regions with and without BTO cladding. The regions without BTO (input and output waveguides) maintain maximum transparency for visible light, while the modulation region with BTO provides the necessary electro-optic functionality, thus maintaining overall system transparency while enabling modulation.
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 efficient phase modulation with reduced propagation and coupling losses, enabling high-speed operation and compatibility with semiconductor manufacturing processes, suitable for quantum computing and optical logic networks.
Implementation Method 1
a membrane including an electro-optical material disposed over the dielectric layer and overlying at least a part of the optical waveguide. The device further includes electrodes configured to apply an electric field to the electro-optical material in a vicinity of the optical waveguide, thereby modulating a phase of a guided optical wave propagating in the waveguide
Data Source
AI summary
An optoelectronic device includes a substrate, an optical waveguide disposed on the substrate, a dielectric layer disposed over the optical waveguide on the substrate, and a membrane comprising an electro-optical material disposed over the dielectric layer and overlying at least a part of the optical waveguide. Electrodes are configured to apply an electric field to the electro-optical material in a vicinity of the optical waveguide, thereby modulating a phase of a guided optical wave propagating in the waveguide.