Angled Grating Coupler for Optical Signal Polarization Alignment
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Conventional copper data channels face signal attenuation and crosstalk due to radiated electromagnetic energy, which are difficult to mitigate effectively with existing techniques, limiting scalability and requiring significant power and complexity.
Innovation Solution
A system and method for coupling a light source assembly to an optical integrated circuit using a laser source assembly with a rotator and angled grating couplers, where the laser generates an optical signal, rotates its polarization, and couples it to a waveguide with a non-zero angle between the grating coupler axis and the plane of incidence, eliminating the need for a separate polarizer and reducing back reflections.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If conventional copper data channels are used to meet bandwidth requirements, then data transmission can be achieved, but signal attenuation and crosstalk occur due to radiated electromagnetic energy, requiring considerable power, complexity, and cable bulk penalties
Solution Approach 1:
The patent replaces copper electrical data channels with optical communication channels. Specifically, it uses a light source (laser or LED) to generate optical signals that modulate data, transmitting information through optical waveguides or fibers instead of electrical signals through copper cables. This substitution eliminates electromagnetic radiation and associated signal attenuation, crosstalk, and power requirements while maintaining or improving bandwidth capacity.
2Reliability
If equalization, coding, and shielding techniques are applied to copper channels to mitigate signal attenuation and crosstalk, then some improvement in reach is achieved, but power consumption, complexity, and cable bulk increase significantly
Solution Approach 1:
The patent eliminates the need for complex equalization, coding, and shielding techniques by replacing the copper electrical channel with an optical channel. The optical transmission medium (waveguide or fiber) inherently prevents electromagnetic radiation and crosstalk, providing reliable signal quality without requiring additional complexity-mitigating components or processing.
3Ease of manufacture
If a conventional grating coupler with zero angle between grating coupler axis and plane of incidence is used, then coupling can be achieved, but back reflections increase and polarization alignment requires separate polarizer components
Solution Approach 1:
The patent introduces asymmetry by using a grating coupler with a non-zero angle (specifically 45 degrees) between the grating coupler axis and the plane of incidence. This angular asymmetry provides two key benefits: it reduces back reflections into the waveguide by directing reflected light away from the input path, and it naturally aligns with the polarization direction of light from standard vertical-cavity surface-emitting lasers (VCSELs), eliminating the need for separate polarizer components.
4Ease of manufacture
If standard grating couplers are used without angle adjustment, then manufacturing is simpler, but polarization alignment with light source requires additional polarizer components increasing complexity and cost
Solution Approach 1:
The patent employs a grating coupler angled at 45 degrees relative to the plane of incidence, creating asymmetric coupling geometry. This angular orientation naturally matches the polarization direction of light emitted by vertical-cavity surface-emitting lasers (VCSELs), which is typically perpendicular to the laser axis. By aligning the grating coupler's sensitive axis with this polarization direction through the 45-degree angle, the design eliminates the need for separate polarizer components while maintaining manufacturing feasibility.
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
This approach enhances signal coupling efficiency, reduces complexity and cost, and improves scalability by using angled grating couplers that align with the polarization of the optical signal, thereby addressing the limitations of copper data channels.
Implementation Method 1
A system and method for coupling a light source assembly to an optical integrated circuit using a laser source assembly
Implementation Method 2
rotates its polarization
Implementation Method 3
an angle between a grating coupler axis that is parallel to the waveguide and a plane of incidence of the optical signal reflected to the angled grating coupler is non-zero
Implementation Method 4
reflects the rotated optical signal onto the grating coupler on the die
Data Source
AI summary
Methods and systems for coupling a light source assembly to an optical integrated circuit are disclosed and may include a system comprising a laser source assembly having a laser, a rotator, and a mirror, where the laser source assembly is coupled to a die including an angled grating coupler and a waveguide. The system may generate an optical signal utilizing the laser, rotate the polarization of the optical signal utilizing the rotator, reflect the rotated optical signal onto the grating coupler on the die, and couple the optical signal to the waveguide, where an angle between a grating coupler axis that is parallel to the waveguide and a plane of incidence of the optical signal reflected to the angled grating coupler is non-zero. The angle between the grating coupler axis and the plane of incidence of the optical signal reflected to the angled grating coupler may be 45 degrees.