A Hot-Polymer Fiber Fabry–Perot Interferometer Anemometer for Sensing Airflow

Lee, Cheng‐Ling; Liu, Kai-Wen; Luo, Shi-Hong; Wu, Meng-Shan; Ma, Chao-Tsung

doi:10.3390/s17092015

Cited by 34 publications

(7 citation statements)

References 15 publications

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“…Another reported system comprises a FPI micro-cavity produced by attaching a polymer to the end of a SMF. In this case, the polymer volume is dependent on the temperature and, therefore, after its initial heating, the hot polymer is cooled down by the air flow, which changes the FPI cavity length and modulates its spectrum [17].…”

Section: Introductionmentioning

confidence: 99%

Optical Fiber Fabry–Perot Interferometer Based Spirometer: Design and Performance Evaluation

et al. 2021

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Spirometry enables the diagnosis and monitoring of multiple respiratory diseases, such as asthma and chronic obstructive pulmonary disease (COPD). In this paper, we present an optical fiber-based device to evaluate the pulmonary capacity of individuals through spirometry. The proposed system consists of an optical fiber containing an intrinsic Fabry–Perot interferometer (FPI) micro-cavity attached to a 3D printed structure that converts the air flow into strain variations to the optical fiber, modulating the FPI spectral response. Besides providing the value of the flow, its direction is also determined, which enables a differentiation between inhale and exhale cycles of breathing. A simulation study was conducted to predict the system behavior with the air flow. The preliminary tests, performed with the FPI-based spirometer led to average values of forced expiratory volume in 1 s (FEV1) and forced vital capacity (FVC) parameters of 4.40 L and 6.46 L, respectively, with an FEV1/FVC index (used as an airway function index) of 68.5%. An average value of 5.35 L/s was found for the peak expiratory flow (PEF). A comparison between the spirometry tests using the presented FPI system and a commercial electronic device showed that the proposed system is suitable to act as a reliable spirometer.

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Section: Introductionmentioning

confidence: 99%

Optical Fiber Fabry–Perot Interferometer Based Spirometer: Design and Performance Evaluation

et al. 2021

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“…A general shortcoming of these types of sensors remains similar as in cases of FBG-based sensors, namely, they possess relatively large-diameter sensing structures, yielding longer response times, typically between 140 and 700 ms [6,7]. Furthermore, the contact surface with the optical fiber is often not negligible [5,6,18], and heat dissipation into the lead-in optical fiber should be taken into consideration.…”

Section: Introductionmentioning

confidence: 99%

Optical Micro-Wire Flow-Velocity Sensor

Njegovec

Pevec

Đonlagić

2021

Sensors

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This paper presents a short response time, all-silica, gas-flow-velocity sensor. The active section of the sensor consists of a 16 µm diameter, highly optically absorbing micro-wire, which is heated remotely by a 980 nm light source. The heated microwire forms a Fabry–Perot interferometer whose temperature is observed at standard telecom wavelengths (1550 nm). The short response time of the sensor allows for different interrogation approaches. Direct measurement of the sensor’s thermal time constant allowed for flow-velocity measurements independent of the absolute heating power delivered to the sensor. This measurement approach also resulted in a simple and cost-efficient interrogation system, which utilized only a few telecom components. The sensor’s short response time, furthermore, allowed for dynamic flow sensing (including turbulence detection). The sensor’s bandwidth was measured experimentally and proved to be in the range of around 22 Hz at low flow velocities. Using time constant measurement, we achieved a flow-velocity resolution up to 0.006 m/s at lower flow velocities, while the resolution in the constant power configuration was better than 0.003 m/s at low flow velocities. The sensing system is constructed around standard telecommunication optoelectronic components, and thus suitable for a wide range of applications.

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“…In contrast, when the FPI's cavity is open, the amplitude, the position of fringes, and the FSR of the fringes will vary depending on the refractive index of the exit medium. Other FPIs designs are based on a set of films deposited at the tip of the optical fiber [9][10][11]. Here, the complexity of the overall spectrum of the reflected intensity distribution of the interferometer increases with the number of films, since it is formed by the superposition of several spectra which are due to multiple reflections occurring between the interfaces of the layers.…”

Section: Introductionmentioning

confidence: 99%

Optical Fiber FP Sensor for Simultaneous Measurement of Refractive Index and Temperature Based on the Empirical Mode Decomposition Algorithm

Rodríguez

Guzmán-Chávez

Baeza-Serrato

et al. 2020

Sensors

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In this work, a dual refractive index and temperature sensor based on an interferometric system and on the empirical mode decomposition (EMD) algorithm is presented. Here, it is shown that the EMD provides a comprehensive way to analyze and decompose complex reflection spectra produced by an interferometric filter build at the tip of an optical fiber. By applying the EMD algorithm, the spectrum can be decomposed into a set of intrinsic mode functions (IMF) from which the temperature and the refractive index can be easily extracted. Moreover, the proposed methodology provides a detailed insight of the behavior of this type of interferometric sensors and allows widening of the dynamic measurement ranges of both variables. Here, for proof of principle purposes, a filter based on a stack of three layers (two of them were thermo-sensitive) was fabricated. Finally, it is shown that the proposed methodology can decompose the experimental measured spectra and to determine the refractive index and the temperature, supporting the mathematical model.

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A Hot-Polymer Fiber Fabry–Perot Interferometer Anemometer for Sensing Airflow

Cited by 34 publications

References 15 publications

Optical Fiber Fabry–Perot Interferometer Based Spirometer: Design and Performance Evaluation

Optical Fiber Fabry–Perot Interferometer Based Spirometer: Design and Performance Evaluation

Optical Micro-Wire Flow-Velocity Sensor

Optical Fiber FP Sensor for Simultaneous Measurement of Refractive Index and Temperature Based on the Empirical Mode Decomposition Algorithm

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