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Design and Implementation of Distributed Ultra-High Temperature Sensing System With a Single Crystal Fiber
摘要： Modern high-temperature processes, such as fossil energy production, nuclear reactors, and chemical reactors lack robust, distributed sensing systems to map temperatures in these high-value harsh-environment systems. Regular silica-fiber-based distributed temperature sensing systems usually only operate at temperatures below about 800 °C. In this paper, we present the design, implementation, and testing of a distributed ultra-high temperature sensing system using Raman scattering intensity, which operates from room temperature to above 1400 °C. Consideration is given to the impacts of thermal radiation, fluorescence, and the multimode nature of unclad single-crystal fiber to optimize the system. Results from picosecond and sub-nanosecond lasers were compared. Measurements were taken with a ～2 m sapphire optical fiber, which represents the longest commercially available length. A spatial resolution of 12.4 cm and position standard deviation of 0.28 mm were achieved up to the maximum testing temperature of 1400 °C, which is a new record for distributed temperature sensing systems.
关键词： Raman scattering,optical fiber applications,high-temperature,Crystals,time-domain analysis
更新于2025-09-23 15:21:21
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Dynamic quasi-distributed ultra-weak fiber Bragg grating array sensing enabled by depth-resolved dual-comb spectroscopy
摘要： Distributed sensing plays an important role in many industrial applications. Sensor arrays consisting of identical ultra-weak fiber Bragg gratings can be applied to such scenarios by monitoring the optical spectral response of the sensors. Yet, the spatial resolution, the sampling speed and the supported number of sensors in the array are mostly determined by the interrogation scheme. While dual optical frequency comb techniques had been successfully demonstrated as a high-resolution spectroscopic technique in metrology, it had been beyond the reach of industrial sensing applications because of its high complexity and costs. It is proposed and demonstrated here that, enabled by a simple fiber-optic, dual-comb spectroscopy setup consisting of a fiber laser without frequency stabilization, interrogation of an ultra-weak fiber sensor array can be realized. High spatial and spectral resolution as well as kHz interrogation speed is achieved in both static and dynamic measurements. It is expected that our depth-resolved dual-comb scheme can measure hundreds of sensors response in less than 1 ms. It is also flexible to deal with targets closely spaced or farther apart from each other. This shows the potential of applying dual-comb spectroscopy to more and more industrial application areas.
关键词： Optical fiber lasers,Optical fiber applications,Optical fiber measurement applications
更新于2025-09-16 10:30:52
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[IEEE 2019 International Workshop on Fiber Optics in Access Networks (FOAN) - Sarajevo, Bosnia and Herzegovina (2019.9.2-2019.9.4)] 2019 International Workshop on Fiber Optics in Access Networks (FOAN) - Measurement of Polarization Transient Effects Caused by Mechanical Stress on Optical Fiber
摘要： The paper deals with measurement of polarization transient effects in single mode optical fiber caused by mechanical stress generated by fiber stretcher. An unexpected event like digging near the buried fiber route can be monitored and evaluated. We performed an experimental verification using polarimeter and balanced photodetector for state of polarization analysis. The results show that the analysis based on polarization splitter and a balanced detector gives sufficient and comparable results to the polarimeter. In addition, it is a cost-effective solution and with the FFT it is possible to perform a quick evaluation of the event frequency.
关键词： Optical fiber polarization,Optical fiber applications,Optical fiber sensors
更新于2025-09-16 10:30:52
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Comparative Investigation of Gamma Radiation Effects on Long Period Gratings and Optical Power in Different Optical Fibers
摘要： This work presents a comparative study regarding the effects of gamma radiation on standard and different radiation hardened optical fibers, by means of arc-induced long period gratings (LPGs) written in these fibers. In particular, the resonance wavelength shift (Δλres) of LPG attenuation bands and the attenuation in the fiber transmitted optical power (ΔP) have been comparatively explored during irradiation. Different responses were observed depending on the fiber model. The Ge-doped fiber exhibits significant changes of both resonance wavelength and optical transmission loss, whereas the pure silica core fiber is mostly insensitive to radiation (Δλres and ΔP keep almost close to zero). Surprisingly, the radiation resistant fiber, with doped core, exhibits significant resonance shift even if with trivial power losses. In addition, by combining these results with numerical modeling of LPGs, we were able to estimate the radiation effects on the optical fibers under investigation, in terms of average refractive index change. These results can be useful for the application of such devices in radiation environments, i.e., for the development of both radiation sensitive and radiation hardened sensors.
关键词： optical fiber sensors,Gamma-ray effects,Gamma-ray detectors,optical fiber applications,Dosimetry,long period gratings
更新于2025-09-11 14:15:04
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Analytical Analysis and Experimental Validation of a Multi-parameter Mach-Zehnder Fiber Optic Interferometric Sensor
摘要： Here we report a simple analytical technique to model a Mach–Zehnder fiber optic interferometric sensors that allow us to predict and calculate via computer simulations parameters that are not easily obtained experimentally. This model was calibrated and compared with experimental data using a 120 mm sensor for measurements of temperature, refractive index and water level. For instance, we were able to calculate the effects on the cladding index caused by the variation of those physical effective parameters. Moreover, this analysis could further our understanding of such sensors and allow us to make predictions about their use in different applications and even their behavior with different sensing lengths.
关键词： optical fiber devices,analytical model,Optical fiber interference,optical fiber applications,optical interferometry
更新于2025-09-04 15:30:14