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Optical Fiber Sensors Based on Microstructured Optical Fibers to Detect Gases and Volatile Organic Compoundsa??A Review
摘要： Since the first publications related to microstructured optical fibers (MOFs), the development of optical fiber sensors (OFS) based on them has attracted the interest of many research groups because of the market niches that can take advantage of their specific features. Due to their unique structure based on a certain distribution of air holes, MOFs are especially useful for sensing applications: on one hand, the increased coupling of guided modes into the cladding or the holes enhances significantly the interaction with sensing films deposited there; on the other hand, MOF air holes enhance the direct interaction between the light and the analytes that get into in these cavities. Consequently, the sensitivity when detecting liquids, gasses or volatile organic compounds (VOCs) is significantly improved. This paper is focused on the reported sensors that have been developed with MOFs which are applied to detection of gases and VOCs, highlighting the advantages that this type of fiber offers.
关键词： humidity and volatile organic compounds,solid core photonic crystal fibers,microstructured optical fibers,gasses,hollow core photonic crystal fibers,suspended core microstructured optical fibers
更新于2025-09-23 15:21:01
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2a??10???μm Mida??Infrared Fibera??Based Supercontinuum Laser Source: Experiment and Simulation
摘要： Mid-infrared supercontinuum (mid-IR SC) sources in the 2–20 μm molecular fingerprint region are in high demand for a wide range of applications including optical coherence tomography, remote sensing, molecular spectroscopy, and hyperspectral imaging. Herein, mid-IR SC generation is investigated in a cascaded silica-ZBLAN-chalcogenide fiber system directly pumped with a commercially available pulsed fiber laser operating in the telecommunications window at 1.55 μm. This fiber-based system is shown to generate a flat broadband mid-IR SC covering the entire range from 2 to 10 μm with several tens of mW of output power. This technique paves the way for low cost, practical, and robust broadband SC sources in the mid-IR without the requirement of mid-infrared pump sources or Thulium-doped fiber amplifiers. A fully realistic numerical model used to simulate the nonlinear pulse propagation through the cascaded fiber system is also described and the numerical results are used to discuss the physical processes underlying the spectral broadening in the cascaded system. Finally, recommendations are provided for optimizing the current cascaded system based on the simulation results.
关键词： soft-glass fibers,nonlinear optics and solitons,supercontinuum generation,chalcogenide fibers,fiber lasers,ZBLAN fibers
更新于2025-09-23 15:21:01
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[IEEE 2019 International Topical Meeting on Microwave Photonics (MWP) - Ottawa, ON, Canada (2019.10.7-2019.10.10)] 2019 International Topical Meeting on Microwave Photonics (MWP) - Heterogeneous multicore fiber for optical beamforming
摘要： We experimentally demonstrate, for the first-time to our knowledge, optical beamforming for microwave phased array antennas implemented with a heterogeneous multicore fiber link. The multicore fiber has been engineered to act as an optical sampled true time delay that allows to implement radiofrequency signal processing in a distributed way. It comprises 7 trench-assisted cores where each core is fabricated with different dimensions and core dopant concentration, as to feature a different group delay and chromatic dispersion behavior. We emulated different radio beamsteering scenarios where the beam-pointing angle is modified by tuning the optical wavelength in a 20-nm range, while squint-beam effects are avoided.
关键词： Microwave Photonics,optical beamforming networks,multicore fibers
更新于2025-09-23 15:21:01
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[IEEE 2019 Workshop on Recent Advances in Photonics (WRAP) - Guwahati, India (2019.12.13-2019.12.14)] 2019 Workshop on Recent Advances in Photonics (WRAP) - A side-polished macro bend fiber sensor for the efficient Detection of petrol adulteration
摘要： A side-polished macro bend fiber sensor is fabricated and demonstrated here. The working principle is based on the macro bending loss and evanescent field absorption. A sensitivity of 90nW/% and 45nW/% are obtained for low and high level of adulteration respectively.
关键词： Side-polished,Sensors,Plastic optical fibers (POFs),Petrol adulteration
更新于2025-09-23 15:21:01
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Single photon interference between bidirectionally extracted photons originating from semiconductor quantum dots
摘要： We report the experimental demonstration of the single-photon interference of bidirectionally extracted photons from epitaxially grown semiconductor quantum dots. The quantum dots were directly connected to single-mode optical fibers. Single-photon nature between transmission and reflection directions was confirmed through detection of antibunching in second-order photon correlation measurements. A Mach–Zehnder interferometer that was naturally formed by introducing the two outputs into a 2 x 2-fiber coupler was used to perform first-order photon correlation measurements.
关键词： single photon interference,single-mode optical fibers,Mach–Zehnder interferometer,semiconductor quantum dots
更新于2025-09-23 15:21:01
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Towards Smart Selective Sensors exploiting a novel approach to connect Optical Fiber Biosensors in Internet
摘要： The selective detection of pollutants in water in a laboratory scenario has been presented by authors exploiting low-cost optical biosensors based on plastic optical fibers (POFs) and biological or bio-mimetic receptors. For instance, the detection in water of naphthalene, perfluoroalkyl and polyfluoroalkyl substances (PFAs) have been investigated with interesting detection limits when compared to those obtained by using different expensive traditional approaches (e.g. liquid chromatography-mass spectrometry with high performances). In this work, we have developed and tested a novel approach used in a smart measuring system to use POF sensors in situ for the remote measures of pollutants in water for smart cities applications. More specifically, we have used different water-glycerin solutions to test the novel sensor system based on a Raspberry PI connected to the Internet and to a spectrometer, a light source, a POF sensor, and two computers connected to Internet used as client and server.
关键词： optical fiber sensors,water quality,pollutants,software,biosensors,Plastic optical fibers (POFs),Internet of Things (IoT)
更新于2025-09-23 15:21:01
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[IEEE 2019 IEEE/AIAA 38th Digital Avionics Systems Conference (DASC) - San Diego, CA, USA (2019.9.8-2019.9.12)] 2019 IEEE/AIAA 38th Digital Avionics Systems Conference (DASC) - Enabling Air-to-Air Wideband Channel Measurements between Small Unmanned Aerial Vehicles with Optical Fibers
摘要： In order to ensure safe and ef?cient operation and to prevent collisions, unmanned aerial vehicles (UAVs) need to communicate with each other with high reliability. To design respective communication systems, accurate air-to-air (A2A) channel models are needed, especially for urban environments, where the channel characteristics are hard to predict due to rich multipath propagation, diffractions and non line of sight (LOS) conditions. For these models, channel measurements in different scenarios are inevitable to model the real-world communication channel. However, small sized UAVs are very limited in carrying payload and in power supply, making it dif?cult or often impossible to use high performing channel-sounding hardware equipment. As a result, less resource demanding hardware with lower performance in the sense of clock synchronization, time resolution or dynamic range is usually applied leading to a limited propagation channel characterization. In this work, we describe a measurement setup that allows using arbitrary channel sounder hardware by exploiting analog optical links in order to enable A2A wideband channel measurements between small sized UAVs. We extend the operation of our MEDAV RUSKDLR channel sounder by guiding a 100 MHz bandwidth radio frequency (RF) signal at 5.2 GHz through two 600 m long optical ?bers attached on two hexacopters after being converted with high bandwidth converters and show the feasibility of this setup with ?rst ?ight trials in an urban scenario.
关键词： Experimental Setup,Optical Fibers,Air-to-Air,Unmanned Aerial Vehicle,Channel Measurement
更新于2025-09-23 15:21:01
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Linear Transformation of Polarization Modes in Coiled Optical Spun Fibers. III. Approximate Analytic Presentation
摘要： We have obtained approximate analytical dependences of the integrated values of effective elliptic birefringence of eigenpolarization modes on the length of coiled spun optical fibers by using approximations of numerical simulation. The dependence of the integrated elliptic birefringence of the polarization eigenmodes on the length of these optical fibers very quickly reaches its limiting value. This dependence also has a complex periodic structure including two substantially different spatial periods. The shape of the considered dependences is determined by the lengths of the polarization beats of the initial linear birefringence of the spun fiber, unperturbed by coiling, and circular birefringence due to torsion of the spun fiber.
关键词： polarization eigenmodes,elliptical birefringence,spun optical fibers
更新于2025-09-23 15:21:01
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Active and Passive Optical Fiber Metrology for Detonation Velocity Measurements
摘要： The reaction rate of an explosive – also called detonation velocity – is the easiest parameter to measure, and also one of the most important in characterizing the process of detonation front propagation in a 1D approach. This paper presents some peculiarities that were observed during the testing of our passive/active optical methods to measure detonation velocity. Both methods were tested using bare optic fiber probes and optic fiber probes protected with a stainless steel tube. The active optical method uses a laser with a wavelength of 660 nm, and the recording system contains a window filter that blocks any radiation outside the wavelength range of 650 to 665 nm. A plastic-bonded explosive based on PETN (seismoplast) was used to test both experimental methods. For rectangular cross-section charges using the passive optical method with the two different probes, the detonation velocities obtained ranged from 7233 to 7324 m/s, with standard deviations between 1.1 and 6.0 %; the experimental results for detonation velocity varied between 7261 and 7351 and were obtained with a standard deviation of 0.6 to 1.7 % for the active optical method.
关键词： Laser light,Detonation radiation,Seismoplast,Optical fibers,Detonation velocity
更新于2025-09-23 15:21:01
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Tests under irradiation of optical fibers and cables devoted to corium monitoring in case of severe accident in a Nuclear Power Plant
摘要： The DISCOMS project, which stands for “DIstributed Sensing for COrium Monitoring and Safety”, considers the potential of distributed sensing technologies, based on remote instrumentations and Optical Fiber Sensing cables embedded into the concrete floor under the reactor vessel, to monitor the status of this third barrier of confinement. This paper focuses on the selection and testing of singlemode (SM) optical fibers with limited RIA (Radiation Induced Attenuation) to be compliant with remote distributed instruments optical budgets, the ionizing radiation doses to sustain, and their reduction provided by the concrete basemat shielding. The tests aimed at exposing these fibers and the corresponding sensitive optical cables, to the irradiation doses expected during the normal operation of the reactor (up to 60 years for the European Pressurized Reactor), followed by a severe accident. Several gamma and mixed (neutron-gamma) irradiations were performed at CEA Saclay facilities: POSé?DON irradiator and ISIS reactor, up to a gamma cumulated dose of about 2 MGy and fast neutron fluence (E > 1 MeV) of 6 x 1015 n/cm2. The first gamma test permitted to assess the RIA at various optical wavelengths, and to select three radiation tolerant singlemode fibers (RIA < 5 dB/100 m, at 1550 nm operating wavelength). The second one was performed on voluminous strands of sensitive cables encapsulating selected optical fibers, up to approximately the same accumulated dose, at two temperatures: 30°C and 80°C. A significant increase of the RIA, without any saturation tendency, appeared for fibers inserted into cables, correlated with the increase of the hydroxyl attenuation peak at 1380 nm. Molecular hydrogen generated by the radiolysis of compounds of the cable is at the origin of this phenomenon. A third gamma irradiation run permitted to measure the radiolytic hydrogen production yield of some compounds of a dedicated temperature cable sample. The efficiency of a carbon coating layer over the silica cladding, acting as a barrier against hydrogen diffusion, was also successfully confirmed. Finally, the efficiency of this carbon coating layer has also been tested under neutron irradiation, then qualified as a protection barrier against hydrogen diffusion in the optical fiber cores.
关键词： carbon coating layer,radiation effects,optical fibers,hydrogen diffusion,gamma,radiolysis,rad-hard optical fiber,neutron,distributed measurement
更新于2025-09-23 15:21:01