Brazed Fiber Bragg Grating Spectrometer for High-Temperature Wellbore Monitoring
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Solution Overview
Problem
Existing optical spectrometers are susceptible to damage from high temperatures, limiting their application in monitoring conditions in wellbores and other harsh environments.
Innovation Solution
An optical spectrometer system that includes a brazed optical grating and a scanning assembly with a piezoelectric member, which allows for alignment and detection of stray light by an optical sensor, even in high-temperature conditions.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conventional optical spectrometers are used, then they can measure optical power as a function of wavelength, but they are susceptible to damage from high temperatures
Solution Approach 1:
The patent replaces conventional mechanical/optical spectrometer components with an optical fiber-based system. The Fiber Bragg Grating acts as a wavelength-selective reflector, and the photodetector measures reflected light intensity at different wavelengths by tuning the grating wavelength through temperature or strain changes, eliminating temperature-sensitive mechanical components
Solution Approach 2:
The system changes the operating parameters by using a tunable Fiber Bragg Grating whose reflection wavelength can be adjusted through temperature or strain. This allows the measurement wavelength to be dynamically changed without moving physical components, enabling the system to operate in high-temperature environments where conventional spectrometers would fail
2Measurement precision
If a Fiber Bragg Grating is used to disperse light, then light at the Bragg wavelength is reflected for detection, but light at other wavelengths passes through without being reflected
Solution Approach 1:
The Fiber Bragg Grating automatically reflects the specific wavelength corresponding to its Bragg condition while transmitting other wavelengths. The system uses this self-selecting property to measure temperature or strain by detecting shifts in the reflected wavelength, eliminating the need for complex wavelength scanning mechanisms
Solution Approach 2:
The single Fiber Bragg Grating serves multiple functions: it acts as a wavelength filter, a temperature sensor, a strain sensor, and a reference standard. By monitoring the reflected wavelength and intensity, the system can simultaneously measure multiple physical parameters without requiring separate sensing components for each parameter
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 system effectively aligns and detects stray light, enabling accurate analysis of electromagnetic energy and providing information about temperature and chemical composition, even in high-temperature environments.
Implementation Method 1
the electrically responsive member has an amount of piezoelectric material
Implementation Method 2
an optical sensor for receiving the stray light and converting the stray light into electricity
Implementation Method 3
a brazed optical grating in communication with electromagnetic energy that is within a bandwidth that is representative of information about a sensed subject, the electromagnetic energy refracted from the brazed optical grating in an azimuthal direction
Implementation Method 4
the electromagnetic energy refracted from the brazed optical grating
Data Source
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AI summary
An optical spectrometer with a tilted or brazed optical grating is useful to identify material composition, estimate physical characteristics, and measure physical conditions. Light from a sample or a space reflects to the grating; and stray light from the grating directed on an optical sensor (which can be a single sensor) and converted into an electrical signal, to obtain information about the sample or space. Examples of scanning include altering an angle the light strays from the optical grating by applying a strain to the optical grating, moving the optical sensor, and installing a mirror in the path of the stray light that reciprocatingly pivots over an angular range. In an example, the optical grating is formed on a light transmission medium that mounts to a piezoelectric element, that expands when energized to apply strain to the grating. In an example, the diffraction grating is a Fiber Bragg Grating.