Central Optical Fiber Layout in Ferrule for Ghost-Reflection Control
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Solution Overview
Problem
Optical sensors face challenges such as low signal-to-noise ratio due to limited scatter cross-section and large measurement distances, requiring precise alignment of optical components to mitigate ghost reflections and stray light, which affect measurement accuracy and precision.
Innovation Solution
The configuration of central optical fibers in a ferrule design involves arranging multiple smaller fibers around a central symmetry axis to direct ghost reflections away from active measurement areas, preventing biased measurements by creating gaps between fibers and using smaller fibers to minimize interference.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If multiple optical channels are used to obtain directional measurement information, then measurement accuracy is improved, but usable laser power and detection signal-to-noise ratio are reduced
Solution Approach 1:
The optical fiber bundle is segmented into multiple individual optical fibers arranged in specific patterns within the ferrule. Each fiber acts as an independent optical channel, allowing parallel measurement of multiple directional parameters. This segmentation enables the system to obtain comprehensive directional information while maintaining adequate laser power for each individual channel through optimized fiber arrangement and gap configuration.
2Measurement precision
If optical components are precisely aligned to improve measurement accuracy, then systematic errors from ghost reflections are reduced, but device complexity increases
Solution Approach 1:
The optical fibers are arranged in an asymmetric pattern within the ferrule, with specific gaps positioned to intercept and block ghost reflections from reaching the detector. This asymmetric configuration creates intentional optical path differences that prevent parasitic reflections from interfering with measurement channels. The asymmetric arrangement simplifies alignment requirements by using the gap geometry itself to define the optical paths rather than requiring precise alignment of multiple components.
Solution Approach 2:
The harmful ghost reflections are extracted and isolated from the measurement paths by strategically positioning gaps between optical fibers. These gaps act as optical barriers that redirect ghost reflections away from the detector, effectively removing the source of systematic error from the measurement system without requiring complex alignment procedures.
3Ease of manufacture
If a single large optical fiber is used in the central channel, then manufacturing is simpler, but ghost reflections cause biased measurements
Solution Approach 1:
The single large optical fiber in the central channel is segmented into multiple smaller optical fibers arranged in a specific pattern. This segmentation creates gaps between the fibers that act as optical barriers to block ghost reflections. The segmented arrangement maintains manufacturing feasibility while eliminating the measurement bias caused by ghost reflections that would occur with a single large fiber.
Solution Approach 2:
The gaps between optical fibers, which could be considered a manufacturing complexity, are converted into a beneficial feature that blocks ghost reflections. By strategically positioning these gaps, the system transforms what could be a source of measurement error into an effective optical barrier that protects measurement channels from parasitic reflections, thereby improving measurement accuracy.
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 design effectively reduces systematic errors from ghost reflections, enhancing measurement precision and accuracy by isolating unwanted reflections from the detection process.
Implementation Method 1
Optical fibers are placed in the central channel such that there are gaps between the optical fibers. The gaps between the optical fibers prevent biased measurements from ghost reflections in the ferrule of the optical system.
Implementation Method 2
a light detection and ranging (LiDAR) system may be used in a vehicle such as an aircraft for determining one or more state variables of the vehicle... The LiDAR system can use an optical interferometer configured to form and project an optical interference pattern on an optical detector.
Implementation Method 3
aligning outer surfaces of an etalon of the optical system such that a normal of the surfaces are parallel
Data Source
AI summary
A method comprises identifying an optical axis with central symmetry in a central channel of a ferrule for an optical system; aligning outer surfaces of an etalon such that a normal of the surfaces are parallel; selecting a sensitivity axis in the central channel; selecting a boundary for the central channel that encompasses at least two fringes during operation of the optical system; defining a minimal radius of a fiber to fit N channels, which are equidistantly populated around the boundary such that N is at least four; selecting fibers in which each fiber substantially has the minimal radius to fit N channels; placing half of the fibers in the central channel such that there are gaps between the fibers; and rotating the fibers around the optical axis such that one fiber is next to the sensitivity axis, or one fiber has a center that intersects the sensitivity axis.