Integrated Active Passive Modulator Tapered Waveguide Coupling
Solution Overview
Problem
Existing photonic beam modulation systems, such as free space acoustic-optics modulators and electro-optic modulators, face limitations in efficiently modulating high-intensity photonic beams across visible and ultraviolet wavelengths with rapid switching and high extinction ratios, requiring significant physical space and experiencing high loss.
Innovation Solution
Integrated active/passive modulators with tapered waveguides made of materials like LiNbO3 and Al2O3, featuring upstream and downstream tapers for optical coupling, allowing for efficient modulation of photonic beams across 350-1000 nm wavelengths with low loss and high extinction ratios, and capable of rapid switching between high and low intensity states.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of energy
If free space acoustic-optics modulators and electro-optic modulators are used for photonic beam modulation, then modulation capability is achieved, but physical space requirements increase and loss increases
Solution Approach 1:
The patent combines the passive waveguide and active modulator components into a single integrated photonic device. The passive waveguide structure is merged with the active modulator region, eliminating the need for separate free space optical paths and reducing overall device footprint while maintaining modulation functionality.
Solution Approach 2:
The patent replaces free space mechanical/optical modulation systems with an integrated photonic waveguide-based modulator. The mechanical/free-space optical path is substituted by guided wave propagation through the waveguide structure, reducing physical space and improving efficiency.
2Speed
If free space modulators are used for high-intensity photonic beams, then modulation is achieved, but switching speed is limited and extinction ratio is reduced
Solution Approach 1:
The patent utilizes changes in the refractive index of the active modulator material in response to applied voltage to dynamically control the optical properties of the waveguide. This parameter change enables rapid switching between high and low intensity states with high extinction ratios, as the refractive index modulation directly affects light propagation without mechanical movement.
3Loss of energy
If integrated active/passive modulators with tapered waveguides are used, then optical coupling efficiency is improved and loss is reduced, but device fabrication complexity increases
Solution Approach 1:
The patent implements tapered waveguide sections with gradually changing cross-sectional dimensions at specific locations where mode matching is required. The taper regions are localized to transition zones between waveguides of different sizes, allowing efficient optical coupling only where needed while keeping the rest of the waveguide structure simple and easy to fabricate.
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 integrated modulators enable efficient modulation of high-intensity photonic beams with low loss and high extinction ratios, reducing physical space requirements and enabling rapid switching between high and low intensity states, suitable for applications like trapped ion quantum computers.
Implementation Method 1
The active waveguide comprises at least one of (a) an upstream taper or (b) a downstream taper. If present, the upstream taper is configured to optically couple the active waveguide to the passive waveguide of the upstream portion. If present, the downstream taper is configured to optically couple the active waveguide to the continuation of the passive waveguide of the downstream portion.
Implementation Method 2
The upstream taper and/or downstream taper extends outward along a unit axis defined by a beam propagation direction through the integrated passive/active modulator unit; in the upstream taper, the active waveguide widens from a upstream taper end width at the upstream end of the active waveguide to a primary active waveguide width at a central region of the active waveguide; and in the downstream taper, the active waveguide narrows from the primary active waveguide width at the central region of the active waveguide to a downstream taper end width.
Data Source
AI summary
Integrated passive/active modulator units, integrated passive/active modulators comprising one or more units, and corresponding methods of fabrication and use are provided. In an example embodiment, a unit comprises an upstream passive portion comprising a passive waveguide; a downstream passive portion comprising a continuation of the passive waveguide; and an active portion between the upstream passive portion and the downstream passive portion. The active portion comprises an active waveguide and electrical contacts in electrical communication with the active waveguide. The active waveguide comprises an upstream taper and/or a downstream taper. The upstream taper is configured to optically couple the active waveguide to the passive waveguide of the upstream portion and the downstream taper is configured to optically couple the active waveguide to the continuation of the passive waveguide of the downstream portion.