Photonic Crystal Waveguide Modulator Design
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Solution Overview
Problem
Conventional integrated optical modulators are large, consume high power, and generate excessive heat, limiting their speed and reliability for optical communication and interconnection applications, while existing photonic crystal modulators face challenges in efficiently coupling electrical signals with light due to inadequate design of electrical structures.
Innovation Solution
A photonic crystal waveguide modulator with an electrically insulating layer and laterally separated conductive regions, allowing for dynamic control of light transmission by applying an alternating voltage signal, which reduces heat generation and enhances modulation efficiency by maximizing the overlap of light field and refractive index changes.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Use of energy by moving object
If conventional integrated optical modulators are used, then light modulation function is achieved, but device size is large and power consumption is high
Solution Approach 1:
The patent utilizes the electro-optic effect to change the refractive index of the photonic crystal waveguide material through applied voltage, thereby modulating light transmission. This parameter change enables compact device size and low power consumption while avoiding excessive heat generation associated with conventional thermal modulation methods
Solution Approach 2:
The patent replaces thermal modulation mechanisms with electro-optic modulation. By applying voltage to induce refractive index changes via the electro-optic effect, the system achieves light modulation without the mechanical heating processes that cause high power consumption and heat generation in conventional modulators
2Volume of moving object
If photonic crystal waveguides are used for compact modulation, then device size is reduced, but electrical signal coupling with light is inefficient due to inadequate electrical structure design
Solution Approach 1:
The patent implements laterally separated conductive regions with different electrical properties within the photonic crystal waveguide structure. This local differentiation of electrical characteristics enables efficient electrical signal coupling while maintaining the compact photonic crystal geometry, addressing the coupling inefficiency problem without sacrificing device miniaturization
Solution Approach 2:
The patent introduces lateral separation of conductive regions in the horizontal plane rather than vertical stacking, creating a two-dimensional electrical structure within the photonic crystal waveguide. This dimensional approach enables effective electrical signal coupling while preserving the compact three-dimensional integration of the device
3Speed
If electro-optic modulation is implemented in photonic crystal waveguides, then modulation speed is increased, but electrical structure design complexity increases
Solution Approach 1:
The patent divides the conductive structure into laterally separated regions within the photonic crystal waveguide. This segmentation simplifies the electrical structure design by creating distinct, manageable conductive zones that are easier to fabricate and control, while still achieving high-speed electro-optic modulation through the underlying photonic crystal mechanism
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 enables compact, low-power, high-speed electro-optical modulation with reduced heat generation, suitable for integrated optoelectronic circuits, and facilitates the integration of multiple devices on a single semiconductor chip, improving device reliability and efficiency.
Implementation Method 1
a photonic band gap exists for photons in a photonic crystal in a continuous range of frequencies where light is forbidden to travel within the photonic crystal regardless of its direction of propagation
Implementation Method 2
dynamic control of light transmission by applying an alternating voltage signal, which reduces heat generation and enhances modulation efficiency by maximizing the overlap of light field and refractive index changes
Data Source
AI summary
An active device for dynamic control of the transmission properties has at least one photonic crystal waveguide that has an electrically insulating layer formed within or near the waveguide core and two lateral conductive regions divided by the insulating layer. An alternating voltage signal induces phase and amplitude changes of electromagnetic wave propagating inside the device. Electromagnetic wave signals propagating through two such active photonic crystal waveguide devices may be mixed to produce at least one output signal through interference. Devices having one or more such active photonic crystal waveguides may be utilized as a tunable optical delay line, a tunable optical filter, a switch, or a modulator. A preferred embodiment comprises a photonic crystal waveguide made of a silicon slab with a periodic array of apertures or oxide columns therein, wherein an silicon oxide layer disposed in the waveguide core separates a p-doped region from an n-doped region.