Retro-reflective Photonic Integrated Circuit for Direction-Insensitive Optical Read-out
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Solution Overview
Problem
Current identification and sensing technologies face challenges with specular reflection, limiting the efficiency of data carrier localization and optical sensor read-out, especially in remote configurations, due to the requirement for perpendicular incidence, which restricts the use of photonic integrated circuits (PICs) in various applications.
Innovation Solution
The development of photonic integrated circuits with non-specular retro-reflective capabilities, allowing light to be coupled into and out of the circuit in directions that are substantially opposite to the incidence direction, enabling direction-insensitive operation and facilitating remote sensing and identification applications.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If specular reflection is used for optical read-out, then the read-out can be performed with a simple optical path, but the read-out device must be positioned perpendicular to the sensor surface, limiting flexibility and remote read-out capability
Solution Approach 1:
The patent inverts the conventional specular reflection principle by implementing retro-reflection, where the optical path is designed to return light to its source direction rather than reflecting at equal angles. This allows the read-out device to be positioned at various angles while still receiving the reflected signal, eliminating the perpendicular positioning requirement without significantly increasing optical path complexity
Solution Approach 2:
The patent introduces retro-reflective elements as intermediaries between the sensor surface and the read-out device. These elements act as mediators that capture incident light and redirect it back toward the source, enabling flexible positioning of the read-out device while maintaining efficient optical coupling
2Adaptability or versatility
If perpendicular incidence is required for specular reflection, then the optical read-out can be achieved with simple alignment, but the application is restricted to line-of-sight configurations, reducing versatility
Solution Approach 1:
The patent applies retro-reflection to invert the conventional reflection geometry, allowing the read-out device to operate from various angles and positions rather than requiring strict perpendicular alignment. This significantly improves adaptability to different read-out configurations while reducing the alignment precision requirements during manufacturing and deployment
3Measurement precision
If data carriers are used for identification, then information can be retrieved from objects, but the localization precision is poor due to large wavelength of RF signals
Solution Approach 1:
The patent replaces RF-based identification systems with optical-based systems using photonic integrated circuits. By substituting electromagnetic radiation in the optical range (with much smaller wavelengths) for RF waves, the system achieves significantly improved localization precision while maintaining the data carrier identification functionality
4Ease of operation
If optical sensors are integrated with optical fibers, then remote read-out is enabled, but the coupling requires stringent alignment requirements
Solution Approach 1:
The patent introduces retro-reflective elements as intermediaries between the optical fiber and the sensor chip. These elements capture light from the fiber and redirect it back through the same fiber, enabling remote read-out capability while significantly reducing the stringency of alignment requirements through the forgiving nature of retro-reflection geometry
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 the spatial resolution and flexibility of identification and sensing applications by allowing non-specular retro-reflective read-out, independent of the light incidence direction, thereby improving the performance of PIC-based systems in various environments and configurations.
Implementation Method 1
at least one input coupling element for coupling incident light from a predetermined incoupling direction into the photonic integrated circuit, and at least one output coupling element for coupling light out of the photonic integrated circuit into an outcoupling direction, wherein the relation between the incoupling direction and the outcoupling direction is different from a relation according to the law of reflection, the incoupling direction and the outcoupling direction being substantially opposite so that retro-reflective operation is obtained
Data Source
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AI summary
A photonic integrated circuit (410) is described comprising at least one signal processing circuit (110). The signal processing circuit (110) comprises at least one input coupling element (120) for coupling incident light from a predetermined incoupling direction into the photonic integrated circuit (410), and at least one output coupling element (130) for coupling light out of the photonic integrated circuit (410) into an outcoupling direction. The relation between the incoupling direction and the outcoupling direction is different from a relation according to the law of reflection and the incoupling direction and the outcoupling direction are substantially the same. Furthermore, an optical sensor probe (400) comprising such a photonic integrated circuit (410) is disclosed. In some embodiments, the optical sensor probe (400) comprises an optical fiber (420) having a first facet and comprises a sensing element physically attached to the first facet, wherein the sensing element comprises said photonic integrated circuit (410).