Fiber-Coupled Microtip Gas Sensing With Stable Optical Coupling
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Solution Overview
Problem
Existing optical sensing technologies face challenges in achieving small-size, cost-effective, and highly sensitive detection of gases and vapors, particularly in remote and human-untouchable environments, with limitations in multiplex detection capability and real-time monitoring.
Innovation Solution
Fiber-coupled microtip sensors utilizing tunable lasers and fiber optics with collimated light paths and stabilized microtips to measure gas concentrations, employing materials like quartz, silica, and ZBLAN glass, and stabilizing units with similar thermal expansion coefficients to maintain precise optical coupling.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Volume of moving object
If optical sensing technologies are made small-size for remote monitoring, then portability and remote detection capability are improved, but sensitivity and measurement precision deteriorate
Solution Approach 1:
The patent embeds the light source, optical components, and detection elements within a compact fiber-optic probe structure. The microtip sensor integrates multiple functional components (collimating lens, beam splitter, detection fiber) into a nested configuration where the detection fiber is positioned within millimeters of the light source at the probe tip, achieving miniaturization while maintaining detection sensitivity through the nested arrangement of optical elements.
Solution Approach 2:
The patent introduces a beam splitter as an intermediary optical component that enables the small probe to achieve high sensitivity. The beam splitter divides the light path to allow simultaneous reference and measurement channels within the compact probe structure, maintaining measurement precision despite the reduced size by mediating the optical interactions between the light source, sample, and detector.
2Reliability
If fiber-optic sensors are used for remote monitoring, then electromagnetic interference and chemical interference are eliminated, but coupling stability and alignment precision become challenging
Solution Approach 1:
The patent merges the light source, optical components, and detection fiber into a single integrated fiber-optic probe assembly. The collimating lens and beam splitter are positioned within the probe housing at fixed distances from the fiber tip, creating a pre-aligned modular unit that eliminates complex field alignment while maintaining optical coupling stability through the integrated design.
Solution Approach 2:
The patent performs preliminary alignment and positioning of optical components during probe manufacturing. The collimating lens is pre-positioned at a specific distance (e.g., 0.5-2 mm) from the fiber tip, and the beam splitter is pre-aligned to achieve optimal optical coupling. This preliminary action ensures stable alignment when the probe is deployed, eliminating the need for complex field calibration.
3Measurement precision
If millimeter-scale fiber tip separation is used for gas detection, then sensitivity to gas concentration changes is improved, but stability of the optical path against thermal expansion deteriorates
Solution Approach 1:
The patent optimizes the separation distance between fiber tips to specific millimeter-scale values (e.g., 0.5-2 mm) based on the absorption characteristics of target gases. This parameter optimization achieves high sensitivity to gas concentration changes while the specific distance range is selected to balance sensitivity with stability against thermal expansion, as smaller separations are less susceptible to thermal drift.
Solution Approach 2:
The patent implements a reference channel through the beam splitter that provides feedback for monitoring optical path stability. By comparing the reference signal with the measurement signal, the system can detect and compensate for drift caused by thermal expansion or other environmental factors, maintaining measurement precision despite changes in the optical path 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
Enables highly sensitive, precise, and accurate detection of gases and vapors, including carbon dioxide, oxygen, and water vapor, with calibration accuracy within 0.1-0.5% of pre-calibrated values, suitable for applications in spacesuits and ISRU processing units.
Implementation Method 1
a first fiber optic connected to the light source, wherein a first end of the first fiber optic is configured to collimate the light
Implementation Method 2
The propagation of light in an optical fiber is confined in the core of the fiber, based on the total internal reflection principle and has near-zero propagation loss within the cladding
Implementation Method 3
the photodetector measures an optical signal induced by a change in characters of the light in the fixed distance between the first end of the first fiber optic and the first end of the second fiber optic
Data Source
AI summary
Systems and methods for fiber optic-coupled microtip sensors are described. Such sensors can be combined with tunable lasers to achieve precision detection of various types of gaseous chemical substances.