Light Coupler Microstructures for Uniform Power Distribution
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Current light couplers for integrated photonic circuits face inefficiencies in coupling light into and out of integrated waveguides, leading to non-uniform power distribution and decay of light signals, which affects illumination quality and the ability to generate focused beams.
Innovation Solution
A light coupler with microstructures on grating lines, positioned according to a non-uniform number density distribution, acts as optical scattering centers to compensate for light decay and achieve a predetermined target power distribution, such as Gaussian, when coupling light into free space, allowing for efficient out-coupling and focusing of light signals.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of energy
If conventional grating couplers are used, then light coupling is achieved, but non-uniform power distribution and light signal decay occur
Solution Approach 1:
The patent applies local quality by varying the density of microstructures across different regions of the grating coupler. The non-uniform number density distribution ensures that regions with higher light intensity have lower microstructure density, while regions with lower intensity have higher density, thereby compensating for light decay and achieving uniform power distribution across the output beam profile.
Solution Approach 2:
The patent changes the parameter of microstructure density from uniform to non-uniform distribution. By adjusting the number density of microstructures as a function of position across the grating coupler, the system compensates for exponential light decay and achieves the desired Gaussian power distribution at the output, transforming the beam profile through parameter variation rather than uniform structure repetition.
2Ease of manufacture
If uniform microstructure distribution is used, then manufacturing is simplified, but light decay compensation and focused beam generation are compromised
Solution Approach 1:
The patent implements local quality by designing different regions of the grating coupler with different microstructure densities tailored to local light intensity requirements. This non-uniform distribution optimizes light coupling efficiency and enables focused beam generation, while still maintaining a systematic fabrication approach that can be implemented using standard photolithography and etching processes.
Solution Approach 2:
The patent applies preliminary action by pre-calculating and pre-designing the non-uniform microstructure density distribution before fabrication. The optimal density profile is determined through theoretical modeling and simulation, allowing the grating coupler to be manufactured with the correct spatial variation in microstructure density, thereby achieving decay compensation and focused beam output without requiring complex real-time adjustments during operation.
3Device complexity
If light decay is not compensated, then device complexity is reduced, but illumination quality and beam focusing capability deteriorate
Solution Approach 1:
The patent achieves illumination quality improvement through local quality variation in the microstructure density. By concentrating microstructures in regions where light intensity is lower and spacing them out in regions of higher intensity, the system compensates for exponential decay and produces a uniform, high-quality illumination profile across the entire output beam, enabling applications such as optical trapping and precision microscopy.
Solution Approach 2:
The patent utilizes parameter changes by varying the microstructure density parameter across the device to compensate for light decay. This systematic parameter variation transforms the exponential intensity profile into a uniform or Gaussian profile, significantly improving illumination quality and enabling focused beam generation without requiring additional optical elements or complex post-processing.
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 solution enhances light out-coupling efficiency, increases uniformity of the generated light cone, enabling the use of larger pinholes and improved illumination, and allows for the generation of focused light beams with increased energy and accuracy.
Implementation Method 1
each of the microstructures forms an optical scattering center, and the microstructures are positioned on the light coupling structure in accordance with a non-uniform number density function
Implementation Method 2
Grating couplers are known in the art. Such coupler may comprise a diffraction grating in a region on top of or below a waveguide
Implementation Method 3
Guided-mode resonance is a phenomenon wherein the guided modes of an optical waveguide can be excited and simultaneously extracted by the introduction of a phase-matching element, such as a diffraction grating or prism
Data Source
Figure 1~4
Figure 2~3
Figure 5~6
AI summary
A light coupler (8) for optically out-coupling a light signal (5) from an integrated waveguide (4) into free space comprises a plurality of microstructures (202). The plurality of microstructures (202) are adapted in shape and position to compensate decay of the light signal (5) when propagating in the light coupler (8), and to provide a power distribution (201) of the light signal (5) when propagating in free space such that this power distribution (201) corresponds to a predetermined target power distribution. Each of the microstructures forms an optical scattering center, and the microstructures are positioned on the light coupler in accordance with a non-uniform number density distribution.