Optical Fiber Tip Micro Anemometer with Spinning Rotor
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Solution Overview
Problem
Existing optical fiber anemometers face challenges with broadband spectrum analysis requirements, power consumption for heating, and difficulty in localized sensing due to their design, which limits their integration into spatially constrained systems and their ability to measure flow effectively in turbulent environments.
Innovation Solution
A micro anemometer is developed using two-photon polymerization microfabrication on an optical fiber tip, featuring a spinning rotor with reflective blades that spin in response to flow, allowing for localized sensing with a simple optical signal and minimal power consumption, enabling operation over a wide flow range.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If traditional optical fiber anemometers use optical resonators (Bragg gratings, Fabry-Perot cavities, surface plasmon resonators), then sensing capability is improved, but broadband spectrum analysis equipment is required which increases device complexity
Solution Approach 1:
The patent replaces complex optical resonator systems with a simple mechanical rotor-anemometer design. Instead of using Bragg gratings, Fabry-Perot cavities, or surface plasmon resonators that require broadband spectrum analysis, the invention uses a flow-driven rotor with reflective blades that modulate a simple optical signal mechanically, eliminating the need for complex spectral analysis equipment.
2Measurement precision
If traditional optical fiber anemometers use active heating elements, then flow sensing is improved, but power consumption increases
Solution Approach 1:
The patent employs a passive rotor design that is directly driven by the kinetic energy of the flowing fluid itself. The rotor with reflective blades rotates in response to flow velocity, modulating the optical signal without requiring any external power source or active heating elements. The flow field provides the energy needed for sensing automatically.
3Stability of the object's composition
If traditional optical fiber anemometers are designed with large footprints, then structural stability is improved, but integration into spatially constrained systems becomes difficult
Solution Approach 1:
The patent integrates the rotor, blades, and optical components into a compact structure mounted on the tip of an optical fiber. The rotor is positioned within close proximity to the fiber core, and the blades are arranged to rotate within a minimal volume while maintaining structural stability. This nested configuration enables integration into spatially constrained systems such as micro-unmanned aerial vehicles.
4Manufacturing precision
If traditional optical fiber anemometers use complex fabrication processes (fiber splicing, UV-curable adhesives, femtosecond laser micromachining), then manufacturing precision is improved, but ease of manufacture decreases
Solution Approach 1:
The patent combines the rotor, blades, and mounting structure into a single integrated component that can be fabricated using additive manufacturing. This merging of multiple parts into one monolithic structure eliminates the need for complex assembly processes such as fiber splicing, adhesive bonding, or multi-step micromachining, significantly simplifying manufacturing while maintaining precision.
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 micro anemometer demonstrates a linear response to flow rates from 9.35-24.28 liters per minute with a sensitivity of 706±43 reflections/LPM, suitable for spatially constrained applications and potential use in aerial vehicles.
Implementation Method 1
Each blade has a reflective undersurface that reflects a light signal back through the optical fiber when center aligned with the optical fiber
Implementation Method 2
The 2PP process utilizes a high-power laser beam to achieve the same polymerization energy with two photons at half the traditional wavelength
Data Source
AI summary
A passive microscopic flow sensor includes a three-dimensional microscopic optical structure formed on a cleaved tip of an optical fiber. The three-dimensional microscopic optical structure includes a post attached off-center to and extending longitudinally from the cleaved tip of the optical fiber. A rotor of the three-dimensional microscopic optical structure is received for rotation on the post. The rotor has more than one blade. Each blade has a reflective undersurface that reflects a light signal back through the optical fiber when center aligned with the optical fiber, the blades of the rotor shaped to rotate at a rate related to a flow rate.