Fiber Optic Pressure Sensor Research Articles

Study on phase demodulation algorithm of fiber optic pressure sensor based on nonlinear differential equation

Fiber optic Fabry–Pérot sensors have been widely developed with unique advantages, such as ease of reuse, resistance to electromagnetic interference, light weight, and their ability to work in extreme environments. There are many demodulation methods that can be applied to fiber optic Fabry–Pérot sensors, including the intensity demodulation method, spectral demodulation, and the phase carrier method, but these demodulation methods cannot meet the requirements that take into account range, speed, and dynamic and static demodulation capabilities. In view of these problems, this paper uses nonlinear differential equations to solve the problem of simultaneous measurement of a large number of ranges and dynamic and static parameters. The measuring interferometer in the demodulation module was built using a polarizing interferometer, which avoids the difficulty in optical wedge processing when using a Fizeau interferometer. Regarding the problems of high and low signal-to-noise ratios of the generated signal, for the problem that the introduction of dispersion in the crystal causes the demodulation result of the traditional demodulation method to be wrong, a nonlinear differential equation is proposed to achieve the correct demodulation of the fiber optic sensor: the slow demodulation speed problem. This paper designs the acquisition, transmission, and processing system based on digital signal processing and a field-programmable gate array, which provide a hardware platform for real-time demodulation. Finally, experiments to test the resolution, linearity, stability, and repeatability of the interferometer were carried out on the designed demodulation system.

A MEMS-Based High-Fineness Fiber-Optic Fabry-Perot Pressure Sensor for High-Temperature Application.

In this paper, a high-fineness fiber-optic Fabry–Perot high-temperature pressure sensor, based on MEMS technology, is proposed and experimentally verified. The Faber–Perot cavity of the pressure sensor is formed by the anodic bonding of a sensitive silicon diaphragm and a Pyrex glass; a high-fineness interference signal is obtained by coating the interface surface with a high-reflection film, so as to simplify the signal demodulation system. The experimental results show that the pressure sensitivity of this sensor is 55.468 nm/MPa, and the temperature coefficient is 0.01859 nm/°C at 25~300 °C. The fiber-optic pressure sensor has the following advantages: high fineness, high temperature tolerance, high consistency and simple demodulation, resulting in a wide application prospect in the field of high-temperature pressure testing.

MP32-02 DEVELOPMENT OF AN AUTOMATED IRRIGATION SYSTEM SYNCHRONIZED WITH AN ULTRA-MINIATURE FIBER-OPTIC PRESSURE SENSOR FOR REGULATING INTRAPELVIC PRESSURE DURING URETEROSCOPY: AN EX VIVO PRECLINICAL STUDY

You have accessJournal of UrologyCME1 May 2022MP32-02 DEVELOPMENT OF AN AUTOMATED IRRIGATION SYSTEM SYNCHRONIZED WITH AN ULTRA-MINIATURE FIBER-OPTIC PRESSURE SENSOR FOR REGULATING INTRAPELVIC PRESSURE DURING URETEROSCOPY: AN EX VIVO PRECLINICAL STUDY Takashi Yoshida, Tadao Matsunaga, Noriko Tsuruoka, Hidefumi Kinoshita, and Youichi Haga Takashi YoshidaTakashi Yoshida More articles by this author , Tadao MatsunagaTadao Matsunaga More articles by this author , Noriko TsuruokaNoriko Tsuruoka More articles by this author , Hidefumi KinoshitaHidefumi Kinoshita More articles by this author , and Youichi HagaYouichi Haga More articles by this author View All Author Informationhttps://doi.org/10.1097/JU.0000000000002581.02AboutPDF ToolsAdd to favoritesDownload CitationsTrack CitationsPermissionsReprints ShareFacebookLinked InTwitterEmail Abstract INTRODUCTION AND OBJECTIVE: Although irrigation flow is essential for maintaining clear visibility and a safe surgical field during flexible ureteroscopy (f-URS), increased intrapelvic pressure (IPP) can be associated with pyelovenous or pyelocaliceal backflow, leading to the risk of febrile urinary tract infection and sepsis postoperatively. This study aimed to assess the feasibility of our automated irrigation system synchronized with an ultra-miniature fiber-optic pressure sensor for regulating IPP in the preclinical setting. METHODS: A fresh cadaveric porcine kidney was used. A 6Fr nephrostomy catheter attached to a pressure transducer and the tip of the 10/12Fr ureteral access sheath (UAS) were placed on the renal pelvis of this model. A fiber-optic pressure sensor, which consisted of a diaphragm pressure sensor (Φ250 μm) and a 2-m optic fiber (Φ140 μm), was set in the working channel of a ureteroscope. The correlation of measured IPP between the fiber-optic pressure sensor and the pressure transducer was assessed. Further, we investigated whether an automatic system could accurately regulate IPP during f-URS. RESULTS: High correlations between the two sensors at each irrigation pressure value (60, 100, 120, and 180 mbar) were observed (all, r=>0.7, p <0.001), likewise when performing bolus irrigation (r=0.98, 95% CI 0.97-0.98, p <0.001). When changing the IPP set value from 5 to 20 mmHg or 20 to 5 mmHg, this automated irrigation system smoothly regulated IPP without overshooting. During the f-URS procedure, although a great change in pressure was observed after insertion or removal of the ureteroscope in the UAS, IPP was immediately and accurately regulated by this system when reaching the renal pelvis. CONCLUSIONS: We developed a new automated irrigation system using an ultra-miniature fiber-optic pressure sensor for controlling IPP during ureteroscopy. This system was a prototype for preclinical use; however, it was feasible and facilitated safety optimization via IPP regulation during f-URS. Source of Funding: None © 2022 by American Urological Association Education and Research, Inc.FiguresReferencesRelatedDetails Volume 207Issue Supplement 5May 2022Page: e531 Advertisement Copyright & Permissions© 2022 by American Urological Association Education and Research, Inc.MetricsAuthor Information Takashi Yoshida More articles by this author Tadao Matsunaga More articles by this author Noriko Tsuruoka More articles by this author Hidefumi Kinoshita More articles by this author Youichi Haga More articles by this author Expand All Advertisement PDF DownloadLoading ...

Occluded insertion loss from intracochlear pressure measurements during acoustic shock wave exposure

Auditory injuries are a common result of high intensity noise exposure, and hearing protective devices (HPDs) can mitigate this injury. Current evaluation methods use manikins to measure ear canal SPLs, but neglect alternate sound conduction pathways. We have previously reported intracochlear pressures in cadaveric human specimens to high-level impulse noise, revealing a substantial bone conducted component. Here, we estimate insertion loss during HPD use from intracochlear pressures in those same specimens. Cadaveric specimens were exposed to shock waves with peak overpressures of 7–83 kPa. Fiber optic pressure sensors were placed in the external, middle, and inner ears and responses measured with ears unoccluded and with four HPDs. Spectral insertion loss was calculated for each exposure level in the frequency domain. Insertion losses calculated from EAC pressures were comparable across levels, consistent with results from acoustic manikins. In contrast, insertion loss calculated from intracochlear pressures were generally lower in magnitude, but increased with the exposure level, likely due to substantial contributions of secondary transmission pathways. Unfortunately, variability in intracochlear pressures limit insertion loss estimate utility. As a proof of concept, we show that averaging multiple exposures increased signal-to-noise considerably, similar noise reduction strategies should be utilized in future studies.

Investigation of explosion-proof fiber-optic pressure sensors using the method of additional loss control

The results of the study of explosion-proof fiber-optic pressure sensors using the method of monitoring additional losses, carried out within the framework of the grant project of the Ministry of Education and Science of the Republic of Kazakhstan AP09562222. Experiments have been conducted on the use of various sources of optical radiation for its use in fiber-optic pressure sensors. The dependence of the strain values is determined, which is represented by a mathematical model with various types of approximation.

Fibre Bragg Grating Based Interface Pressure Sensor for Compression Therapy

Compression therapy is widely used as the gold standard for management of chronic venous insufficiency and venous leg ulcers, and the amount of pressure applied during the compression therapy is crucial in supporting healing. A fibre optic pressure sensor using Fibre Bragg Gratings (FBGs) is developed in this paper to measure sub-bandage pressure whilst removing cross-sensitivity due to strain in the fibre and temperature. The interface pressure is measured by an FBG encapsulated in a polymer and housed in a textile to minimise discomfort for the patient. The repeatability of a manual fabrication process is investigated by fabricating and calibrating ten sensors. A customized calibration setup consisting of a programmable translation stage and a weighing scale gives sensitivities in the range 0.4–1.5 pm/mmHg (2.6–11.3 pm/kPa). An alternative calibration method using a rigid plastic cylinder and a blood pressure cuff is also demonstrated. Investigations are performed with the sensor under a compression bandage on a phantom leg to test the response of the sensor to changing pressures in static situations. Measurements are taken on a human subject to demonstrate changes in interface pressure under a compression bandage during motion to mimic a clinical application. These results are compared to the current gold standard medical sensor using a Bland–Altman analysis, with a median bias ranging from −4.6 to −20.4 mmHg, upper limit of agreement (LOA) from −13.5 to 2.7 mmHg and lower LOA from −32.4 to −7.7 mmHg. The sensor has the potential to be used as a training tool for nurses and can be left in situ to monitor bandage pressure during compression therapy.

Characterization of Systemic and Regional Hemodynamics and Vascular Dysfunction in Mice with Fecal Induced Peritonitis.

Sepsis is associated with circulatory dysfunction contributing to disturbed blood flow and organ injury. Decreased organ perfusion in sepsis is attributed, in part, to the loss of vasoregulatory mechanisms. Identifying which vascular beds are most susceptible to dysfunction is important for monitoring the recovery of organ function and guiding interventions. This study aimed to investigate the development of vascular dysfunction as sepsis progressed to septic shock. Anesthetized C57Bl/6 mice were instrumented with a fiberoptic pressure sensor in the carotid artery for blood pressure measurements. In subgroups of mice, regional blood flow measurements were taken by positioning a perivascular flow probe around either the left carotid, left renal, or superior mesenteric arteries. Hemodynamic parameters and their responsiveness to bolus doses of vasoactive drugs were recorded prior to and continuously after injection of fecal slurry (1.3 mg/g body weight) for 4 h. Fecal slurry-induced peritonitis reduced mean arterial pressure (62.7 ± 2.4 mmHg vs. 37.5 ± 3.2 mmHg in vehicle and septic mice, respectively), impaired cardiac function, and eventually reduced organ blood flow (71.9%, 66.8%, and 65.1% in the superior mesenteric, renal, and carotid arteries, respectively). The mesenteric vasculature exhibited dysregulation before the renal and carotid arteries, and this underlying dysfunction preceded the blood pressure decline and impaired organ blood flow.

Intracranial Pressure Monitoring In Nontraumatic Intraventricular Hemorrhage Rodent Model.

Survivors of intraventricular hemorrhage are often left with significant long-term memory impairment; thus, research utilizing intraventricular hemorrhage animal models is essential. In this study, we sought out ways to measure intracranial pressure, mean arterial pressure, and cerebral perfusion pressure during nontraumatic intraventricular hemorrhage in rodents. The experimental design included three Sprague Dawley groups: sham, standard 200 µl intraventricular hemorrhage, and vehicle control groups. By introducing an intraparenchymal fiberoptic pressure sensor, precise intracranial pressure measurements were obtained in all groups. Cerebral perfusion pressures were calculated with the knowledge of intracranial pressure and mean arterial pressure values. As expected, the intraventricular hemorrhage and vehicle control groups both experienced a rise in the intracranial pressure and subsequent decline in cerebral perfusion pressure during intraventricular injection of autologous blood and artificial cerebrospinal fluid, respectively. The addition of an intraparenchymal fiberoptic pressure sensor is beneficial in monitoring precise intracranial pressure changes.

Membrane-free fiber-optic Fabry-Perot gas pressure sensor with Pa-level resolution

A highly sensitive fiber-optic Fabry-Perot sensor based on femtosecond (fs) laser micromachining is proposed and demonstrated for gas pressure measurement. The sensor is fabricated by inserting two single mode fibers (SMFs) into a capillary. A fs laser is employed to drill a micro-channel on the wall of the capillary to allow gas diffuse in. Due to the linear relationship between the pressure and the refractive index (RI) of the gas, the gas pressure can be detected by investigating the optical cavity length. The signal is demodulated by using the white-light interferometry (WLI) method based on digital cross-correlation technology. The sensitivity of the proposed pressure sensors is investigated theoretically and experimentally. The sensitivity of the sensor with a cavity length of 2926 μm is 7702 nm/MPa. In addition, a good repeatability and a high resolution of 4.9 Pa of the proposed sensor have been demonstrated. Due to the miniature size, wide dynamic range, high stability, high sensitivity and high resolution, the membrane-free fiber-optic Fabry-Perot sensor with Pa-level resolution has a wide application for gas pressure detection.

A1190 - Development of an automated irrigation system synchronized with an ultra miniature fiber optic pressure sensor for regulating intrapelvic pressure during ureteroscopy: An ex vivo preclinical study

A1190 - Development of an automated irrigation system synchronized with an ultra miniature fiber optic pressure sensor for regulating intrapelvic pressure during ureteroscopy: An ex vivo preclinical study

Vaginal pressure sensor measurement during maximal voluntary pelvic floor contraction correlates with vaginal birth and pelvic organ prolapse-A pilot study.

To measure the force applied along the anterior and posterior vaginal walls in a cohort of 46 patients measured by a fiber-optic pressure sensor and determine if this correlates with vaginal parity and pelvic organ prolapse (POP). An intravaginal fiber-optic sensor measured pressure at nine locations along the anterior and posterior vaginal walls during a maximal voluntary pelvic floor muscle contraction (MVC). An automated probe dilation cycle measured the tissue resistance incorporating the vagina and surrounding anatomy. MVC and resting tissue resistance (RTR) were assessed between subjects grouped by the number of vaginal births and prolapse stage. A previous vaginal birth was associated with a significant threefold decrease in the overall anterior pressure measurement during MVC. Decreased anterior pressure measurements were observed at Sensors 1 and 3 (distal vagina) and, posteriorly at Sensors 4-6 (midvagina). Women with Stage 2 posterior prolapse exhibited a decreased MVC pressure in the midvagina than those with Stage 0/1. In this pilot study, there was no difference in the vaginal wall RTR according to previous vaginal birth or stage of prolapse. This pilot study found that a decrease in vaginal pressure measured during MVC is associated with vaginal birth and with posterior POP. Greater sample size is required to assess the role of resting tissue pressure measurement.

All-sapphire fiber-optic pressure sensors for extreme harsh environments.

In this paper, an all-sapphire fiber-optic Fabry-Perot (F-P) pressure sensor is proposed. The sapphire pressure-sensitive diaphragm with low surface roughness is fabricated by MEMS wet etching. The direct bonding process is adopted to bond the sapphire-sensitive diaphragm and substrate together. And the sapphire fiber is adopted to be the lead-in fiber to ensure the sensor's resistance to high temperature. The performance of the sensor is tested within a pressure range of 0.1∼5 MPa and within the temperature range from room temperature to 1200°C. Experimental results show that the sensor could work stably at the temperature of 1200°C. The pressure sensitivity reaches up to 15nm/MPa. The nonlinearity of the sensor is 0.96% FS (full scale), and the relative resolution reaches 0.12%FS. The all-sapphire F-P sensor could be used for high-pressure testing in a high-temperature environment.

High-Precision Optical Fiber Temperature and Pressure Sensor and Its Application in Production Wells

High-Precision Optical Fiber Temperature and Pressure Sensor and Its Application in Production Wells

3d Printing of a Fiber Optic Pressure Sensor

3d Printing of a Fiber Optic Pressure Sensor

Compensation for Temperature Drift in Frequency-Modulated Continuous-Wave Interference Fiber Optic Pressure Sensor

Compensation for Temperature Drift in Frequency-Modulated Continuous-Wave Interference Fiber Optic Pressure Sensor

Double F-P Interference Optical Fiber High Temperature Gas Pressure Sensor Based on Suspended Core Fiber

A compact and simple double F-P interference optical fiber optic gas pressure sensor based on suspended core structure is proposed and demonstrated. The sensor is formed by splicing a Section of thin-walled grapefruit photonic crystal fiber (G-PCF) with single-mode fiber (SMF). By adjusting the special fusion parameters, a short air-cavity region is formed in the G-PCF next to the splicing point with the SMF segment, and the other end of the G-PCF segment is open to the atmosphere. The output interference spectrum of the sensor comprises of two spectral parameters that have different sensitivities to temperature and gas pressure. One of them is the wideband envelope that is associated with the air-cavity and it is only sensitive to the gas pressure but insensitive to the change of ambient temperature. This property is particularly useful for addressing the complex temperature-pressure cross sensitivity of both spectral parameters. The research findings indicate that the sensor can perform an accurate measurement for gas pressure in dynamic range of 0-1.0 MPa under the high temperature condition up to 500 &#x00B0;C.

Underwater fiber-optic salinity and pressure sensor based on surface plasmon resonance and multimode interference.

In this paper, an underwater fiber-optic sensor based on surface plasmon resonance (SPR) and multimode interference (MMI) is presented for simultaneous measurement of salinity and pressure. This sensor is based on a single-mode-multimode-single-mode-multimode-single-mode structure with a gold film deposited on the middle single-mode fiber and the fiber structure is wrapped around an elastic cylinder to constitute a sensing head. In the fiber structure, the SPR region produces a resonance dip to measure salinity, and the independent MMI region achieves narrow and salinity-insensitive interference dips to measure pressure. Performance of the sensor is predicted by calculation, and the MMI spectrum is simulated by using the finite-difference beam propagation method. By experimental tests for salinity and pressure, the sensitivities of 0.36 nm/‰ and -1.42nm/MPa are achieved, respectively, and the cross talk is also proved to be insignificant. This study provides an important application direction for SPR-MMI sensors and a prospective method for ocean detection.

A novel flow and pressure catheter for complete interventional cardiology physiology management

Abstract Ischemia with No Obstructive Coronary Artery (INOCA) in angina patients increases the risk of major cardiac events, with a 1.5x increased mortality rate. There is a link between COVID-19 infection and impairment in the myocardial micro-vasculation which may cause an increase of INOCA patients. Fractional Flow Reserve (FFR), is the standard of care in cardiology but its diagnostic function is only related to Obstructive Coronary Artery disease (or epicardial) and it is ineffective with INOCA. The lack of effective and accurate tools for timely evaluation of coronary impairments creates a clinical unmet need. The PhysioCath catheter was developed within the Eurostars project “FP-Catheter, E!113577” aims to resolve this need a provide an effective tool to interventional cardiologists. The main project outcome is a catheter prototype equipped with a blood flow velocity sensor based on a thermo-convection principle, and a fiber optic pressure sensor (based on Fabry-Perot principle). While the use of Fabry-Perot type of sensor is already standard in the industry, the use of a thermo-convection sensor represents a progress with respect the state of the art. The sensor creates an overheat of 7°C above the physiological blood's temperature (considered as being within the safety limits), and it exchanges thermal power with the blood stream. The power is then measured and converted to velocity by means of a calibration curve. The project encompassed interviews with 14 clinical experts, the summary of the interviews indicated that the preferred form of the device is an over the wire microcatheter, with rapid exchange. Within the project then, it was developed a 3Fr microcatheter, with a rapid exchange section of 24cm. Both pressure sensor and flow velocity sensor were integrated in this embodiment. Finally, the PhysioCath prototype was evaluated in a bench test study. The test setup was composed by an anatomical silicone phantom of the aortic root and the coronaries (Elastrat, Geneva, Switzerland), perfused with a peristaltic pump (Harvard Apparatus, Holliston MA, US). The measurements performed by the flow velocity sensor were compared against and external doppler flow velocity sensor. While the pressure measurement was assessed for stability and presence of drift. The data processing revealed and extreme accuracy in the measurement of flow based indexes like CFR (±6% variability), accuracy of the blood flow velocity measurement (±10%), and extreme stability in the measurement of both pressure and flow velocity. In the second part of the project (that is currently ongoing), it will be studied the performance of the device within an animal setting. In conclusion, the PhysioCath device is a microcatheter integrating bot pressure measurement and blood flow velocity measurement. Its performance is of very high accuracy and stability, that represent a main step ahead with respect the current state of the art, based mainly on thermodilution. Funding Acknowledgement Type of funding sources: Public grant(s) – EU funding. Main funding source(s): Eureka-Eurostars Test benchMicrocatheter prototype

High-sensitive fiber-optic pressure sensor based on Fabry-Perot interferometer filled with ultraviolet glue film and Vernier effect

A high sensitivity fiber-optic pressure sensor based on Fabry-Perot interferometer filled with ultraviolet (UV) glue film and Vernier effect was proposed and demonstrated. The sensor is composed of a sensing Fabry-Perot (FP) cavity and a reference FP cavity in parallel. The sensing cavity is fabricated by splicing a section of silica tube (ST) to the lead-in single-mode fiber (SMF), and filling a thin layer of UV glue at the end-face of the ST. The reference cavity is made by sandwiching a section of ST between two SMF. The parallel cavities generate the Vernier effect due to a similar free spectrum range, which significantly improves the sensitivity of the sensor. The proposed sensor with good repeatability and reliability was used to monitor the change of air pressure, and provided a high sensitivity of −38.3 nm/MPa. The sensor exhibited the potential applications in the fields of aerospace industry, biological diagnostics and environmental monitoring.

Fiber optic pressure measurement on a complex outer winglet model with active flow control actuators

The next generation of aircraft requires novel approaches on lift increase and drag reduction technologies as active flow control to counter local flow separations. Testing and monitoring its effectiveness in flight require precise pressure evaluation as a possible control input. Pressure-based measurements of local flow separation are challenging utilizing conventional electrical pressure sensors. These sensors might show degradation of their long-term performance in harsh environments, e. g., in real aircraft applications, due to their low overload protection, susceptibility to electromagnetic influences, and corrosion. Fiber optic measurements overcome those challenges and promise to be a robust sensing solution. We investigate the potential application of a novel fiber optic measurement system that monitors the active flow control system's effectiveness. Furthermore, the results are compared to conventional static pressure measurements. Due to the high-frequency capabilities of the fiber optic sensors, the dynamic behavior of the boundary layer separation and vortex generation was captured in the frequency domain. An industry-relevant outer wing was equipped with 25 fiber optic pressure sensors positioned at one wingspan section for this experiment. The experiments were conducted at a Reynolds number Re=1.1⋅106and a Mach number Ma=0.12. Wind tunnel testing results show that fiber optic pressure sensors can measure aerodynamic characteristics and, furthermore, even allow a detailed look at the dynamic behavior.