Fractal Waveguide Light-Collecting Structure for Optical Systems
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Solution Overview
Problem
Current light collecting structures for laser beam optical communication receivers and LIDAR systems face inefficiencies due to additive optical signal losses and phase shifts, particularly when using linear structures and modules with assembly offsets or atmospheric distortions, which reduce the collected optical power.
Innovation Solution
A light collecting structure comprising modules with a fractal waveguide network arrangement to minimize additive losses and a phase modulation system to compensate for phase shifts between modules, ensuring maximum optical power transmission to a photodetector.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If a linear waveguide network structure is used to connect elementary light collectors, then the structure is simple to manufacture, but the additive accumulation of optical signal losses along each row waveguide considerably limits the collecting efficiency
Solution Approach 1:
The patent transforms the traditional linear one-dimensional waveguide network into a two-dimensional mesh network architecture. Elementary light collectors are connected to multiple waveguides in a grid pattern rather than being arranged in simple parallel rows, allowing light to reach the output through multiple parallel paths and reducing the additive loss accumulation that plagues linear structures.
Solution Approach 2:
The waveguide network is segmented into multiple independent waveguide paths that converge at the optical output. Instead of a single long row waveguide where losses accumulate additively, the network divides the collection into multiple shorter waveguide segments that can be independently optimized and whose losses do not accumulate in the same manner.
2Ease of manufacture
If modules are assembled with offsets or when wavefront passes through inhomogeneous atmosphere, then the structure can be manufactured and deployed, but phase shifts between modules reduce the optical power at the output
Solution Approach 1:
The patent introduces dynamic phase compensation mechanisms that can adjust the phase of individual module outputs in real-time. This allows the system to adapt to assembly offsets and atmospheric disturbances, maintaining constructive interference and maximizing optical power at the output despite variations in module positioning or wavefront distortion.
Solution Approach 2:
The system employs feedback control where the phase shifts of individual modules are monitored and adjusted based on the overall interference pattern at the optical output. This feedback mechanism compensates for assembly offsets and atmospheric phase distortions by dynamically tuning module phases to achieve optimal constructive interference.
3Loss of energy
If telescope-type optics are used to collect light, then the light collection efficiency can be high, but the structure becomes bulky and heavy
Solution Approach 1:
The patent replaces traditional mechanical telescope optics with a planar photonic integrated circuit structure. Instead of using bulky mirrors and lenses to focus light, the system uses sub-wavelength elementary light collectors and waveguide networks to achieve efficient light collection in a thin, flat configuration that is suitable for integration into aircraft fuselages.
Solution Approach 2:
The invention transitions from three-dimensional telescope optics to a two-dimensional planar structure. The light collection function is achieved through a flat array of elementary collectors coupled to waveguides in the same plane, eliminating the need for deep optical paths and bulky focusing components while maintaining collection efficiency.
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 fractal waveguide network enhances light collection efficiency by reducing radiation losses and the phase modulation system compensates for phase shifts, resulting in improved optical power transmission and collection efficiency, even under conditions of assembly offsets and atmospheric distortions.
Implementation Method 1
a waveguide network which is carried by the substrate, and which optically connects each elementary light collector of the module to an optical output of this module
Implementation Method 2
a phase modulation system to compensate for phase shifts between modules, ensuring maximum optical power transmission to a photodetector
Data Source
Figure 1
Figure 2~3a
Figure 3b
AI summary
A light-collecting structure (100) comprising a plurality of modules (1, 2, 3…), each module comprising a large number of elementary light collectors which are juxtaposed on a substrate of the module. According to a first aspect of the invention, the elementary light collectors are coupled, within each module, to an optical output (S1, S2, S3…) of the module by an arrayed waveguide grating which has a fractal layout. According to a second aspect of the invention, optical transfer paths (1C, 2C, 3C…) which respectively connect the optical outputs of the modules to a photodetector (101) comprise phase modulators (20) for re-synchronising radiating portions relative to each other, which radiating portions are individually collected by the modules. Each aspect of the invention contributes to reducing optical signal losses which occur in the structure, whereby maximising a light power that is transmitted to the photodetector. Such a light-collecting structure can advantageously be used in a laser beam optical communication receiver or in a LIDAR system.