Grated Optical Waveguide Integrated Capacitor Modulation Efficiency
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Solution Overview
Problem
Conventional optical phase shifters in silicon photonic integrated circuits suffer from low modulation efficiency, high energy consumption, slow-speed operation, and fabricating complexities due to the weak plasma dispersion effect in silicon.
Innovation Solution
An optical device with a waveguide integrated capacitor structure is proposed, featuring a grating in the optical waveguide and an insulating layer sandwiched between the optical waveguide and a high refractive index electrically conductive layer, enhancing modulation efficiency and energy efficiency.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Use of energy by moving object
If conventional optical phase shifters (PN junction, PIN junction, MOSCAP) are used in silicon photonic integrated circuits, then phase shifting function is achieved, but modulation efficiency is low and energy consumption is high
Solution Approach 1:
The patent merges the optical waveguide and capacitor into a single integrated structure where the waveguide serves dual purposes: guiding optical signals and storing electrical charge. This integration eliminates the need for separate phase shifter components, reducing energy consumption while improving modulation efficiency through the combined electro-optic and capacitive effects.
Solution Approach 2:
The patent utilizes changes in the refractive index of the waveguide material in response to electrical voltage application. By controlling the voltage across the integrated capacitor, the refractive index is dynamically adjusted, enabling efficient phase modulation with lower energy consumption compared to conventional methods.
2Speed
If conventional optical phase shifters are used, then phase shifting is achieved, but operation speed is slow
Solution Approach 1:
The patent replaces conventional mechanical or chemical carrier injection/depletion mechanisms with a direct electrostatic field-based modulation approach. The integrated capacitor structure allows for rapid voltage switching that directly modulates the refractive index, achieving higher operation speeds while maintaining reliable phase shifting.
3Ease of manufacture
If conventional phase shifters are used, then phase shifting function is achieved, but fabricating complexity increases
Solution Approach 1:
By integrating the capacitor and waveguide into a single structure, the patent reduces the number of separate fabrication steps and components required. This merged design simplifies the manufacturing process while maintaining the necessary functional complexity for efficient phase 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 proposed optical device achieves significantly improved modulation efficiency, reduced power consumption, and simplified design, making it suitable for high-speed and energy-efficient optical communication systems.
Implementation Method 1
the optical phase shifters used in silicon photonic integrated circuits are generally designed to induce a phase shift in the optical signal using a plasma dispersion effect
Implementation Method 2
an insulating layer formed over the optical waveguide, and an electrically conductive layer formed over the insulating layer... the optical waveguide, the insulating layer, and the electrically conductive layer form a waveguide integrated capacitor
Data Source
AI summary
Examples described herein relate to an optical device that entails phase shifting an optical signal. The optical device includes an optical waveguide having a first semiconductor material region and a second semiconductor material region formed adjacent to each other and defining a junction therebetween. Further, the optical device includes an insulating layer formed on top of the optical waveguide. Moreover, the optical device includes a III-V semiconductor layer formed on top of the insulating layer causing an optical mode of an optical signal passing through the optical waveguide to overlap with the first semiconductor material region, the second semiconductor material region, the insulating layer, and the III-V semiconductor layer thereby resulting in a phase shift in the optical signal passing through the optical waveguide.