- 标题
- 摘要
- 关键词
- 实验方案
- 产品
-
Implementation of Optical Fiber Post-Mortem Dose Measurements: a Proof of Concept
摘要： We describe the implementation of a versatile system and corresponding method to perform fast post-mortem optical attenuation measurements on irradiated Optical Fibers (OFs) for dosimetry purposes. The measurement is based on the Radiation Induced Attenuation (RIA) phenomenon. We employ a dual wavelength Optical Time Domain Reflectometer (OTDR) coupled with a suitable radiation sensitive OF. We demonstrate that radiation dose levels higher than 100 Gy(SiO2) can be measured efficiently with 1 m long samples. The accuracy of the measurement increases with the increasing radiation dose if the length of the sample is kept fix. We also highlight possible limitations of our approach and, more generally, limitations related to perform accurate RIA measurement (online or post-mortem) on short single mode OF samples. The technological solution we propose can be tailored to address different radiation environment.
关键词： Optical fibers,P-doped,radiation sensitive,Dosimetry,Radiation Induced Attenuation,CERN
更新于2025-09-11 14:15:04
-
Distributed Fiber Sensing and Dynamic Rating of Power Cables || Optical Fibers, Connectors, and Cables
摘要： This chapter introduces the types of fibers available in the industry for DTS applications, the types of optical connectors, and their relevance in the context of distributed sensing applications. It also discusses how they may be incorporated into power cable transmission land and submarine corridors as well as the potential challenges that one may encounter during installation, particularly when fibers are embedded in the power cable itself.
关键词： Installation challenges,Connectors,Submarine corridors,DTS applications,Distributed sensing,Optical Fibers,Power cable transmission,Cables
更新于2025-09-11 14:15:04
-
Broadband visible-to-NIR ASE from Bismuth doped optical fibers: a window towards lasing
摘要： We report broadband ASE within 650-825nm, peaking at 655nm, 680nm, 715nm, from Bismuth (Bi) doped optical fibers (BDFs) under 533nm core-pumping excitation technique; 715nm peak was prominent among others. Fiber preforms were fabricated through MCVD process associated with solution doping technique using Bi-,Yttrium/Lithium co-doped phosphosilicate, germanosilicate glasses (BYPS/BYGS/BLGS) as core materials. Optimum fiber lengths providing maximum ASE were 15cm for BYPS and 35cm for BYGS fibers. Possible issues behind strong ASE without any lasing were demonstrated using modal analysis of BDFs at 533nm and 715nm. This study is a step towards developing visible-to-NIR laser using BDFs of such types.
关键词： ASE,Bismuth doped optical fibers,visible-to-NIR,lasing
更新于2025-09-11 14:15:04
-
[IEEE 2019 Conference on Lasers and Electro-Optics Europe & European Quantum Electronics Conference (CLEO/Europe-EQEC) - Munich, Germany (2019.6.23-2019.6.27)] 2019 Conference on Lasers and Electro-Optics Europe & European Quantum Electronics Conference (CLEO/Europe-EQEC) - Power Dependent Noise Performance of fs Supercontinuum Generation in Normal Dispersion Fibers with a Long Zero-Dispersion Wavelength
摘要： One of the requirements for generating a low noise supercontinuum (SC) in a normal dispersion fiber using a femtosecond (fs) pump is to have the minimum absolute dispersion wavelength to be close to zero in order to avoid parametric Raman noise. SC generation in all-normal dispersion fibers can under certain requirements provide a highly coherent spectrum, which is of key importance to a large range of imaging and spectroscopy applications. Key requirements to avoid Raman noise and noise from polarization mode instability (PMI) is to have a sufficiently low peak power (P0), short pulse length (T0), short fiber length, and high fiber birefringence. Silica microstructured fibers (MSFs) pumped with 1550 nm fs lasers is an attractive platform to generate a low noise SC due to their technological maturity. We therefore fabricated a low-loss silica MSF (using 2 cladding sections with different hole sizes) with weak dispersion at 1500 nm and experimentally studied SC generation at low peak powers using a 1550 nm, 125 fs pump. The group velocity dispersion (β2) profile of the fiber is shown in Fig. 1(a). Since the dispersion at the pump is weak, a low P0 can be used to generate a broad SC. A further advantage of using low peak powers is the possibility of avoiding PMI. The requirement of weak dispersion at 1550 nm leads to a fiber design with a zero dispersion wavelength (ZDW) at 1.8 μm. The SC generated with up to P0 =9 kW does not cross the ZDW and has low relative intensity noise (RIN) as was demonstrated numerically and experimentally [see Fig. 1(b)]. To study the effect of higher input power, where the SC crosses into the anomalous dispersion region (ADR), we performed numerical modelling, taking into account both quantum noise and laser amplitude noise by adding 1% fluctuation in P0 with constant P0T0. At P0 =45 kW the broadening is initially from self-phase modulation and optical wave breaking in the normal dispersion region (NDR), but later the SC broadens into the ADR and develops into solitons. These solitons generate trapped dispersive waves that are very noisy and move through the low-noise spectrum in the NDR [see Fig. 1(c+d)]. Our results using the novel MSF for low-noise normal dispersion SC generation at 1550 nm, demonstrate that a long wavelength ZDW can be tolerated, as long as the peak power is sufficiently low to avoid power crossing into the ADR.
关键词： zero-dispersion wavelength,femtosecond pump,low noise,normal dispersion fibers,supercontinuum generation
更新于2025-09-11 14:15:04
-
[IEEE 2019 IEEE 2nd 5G World Forum (5GWF) - Dresden, Germany (2019.9.30-2019.10.2)] 2019 IEEE 2nd 5G World Forum (5GWF) - The Optical Fiber and mmWave Wireless Convergence for 5G Fronthaul Networks
摘要： In this paper, we have addressed and reported the principal technologies part of the next generation mobile fronthauling networks, namely 5G fronthaul. We also described the main features of these technologies and illustrated their benefit via current and challenging bottleneck network conditions by involving real world scenarios with high demand for innovative solutions. These technologies (such as ribbon optical fibers, RoF, passive WDM, mmWaves) will be most likely implemented in the 5G fronthaul infrastructure. Among these technologies, several technical challenges remain to be addressed such as cost-efficient hardware solutions for RoF transceivers, simple adaptation of RoF techniques over ribbon fibers, optical beamforming in integrated photonics, seamless interfaces between the ribbon fiber media and the radiating elements in the RU sites, and finally remote power distribution to RUs from CO premises.
关键词： 5G,fronthaul,mmWave,RoF,ribbon fibers,WDM,C-RAN
更新于2025-09-11 14:15:04
-
Laser-Induced Deposition of Carbon Nanotubes in Fiber Optic Tips of MMI Devices
摘要： The integration of carbon nanotubes (CNTs) into optical fibers allows the application of their unique properties in robust and versatile devices. Here, we present a laser-induced technique to obtain the deposition of CNTs onto the fiber optics tips of multimode interference (MMI) devices. An MMI device is constructed by splicing a section of no-core fiber (NCF) to a single-mode fiber (SMF). The tip of the MMI device is immersed into a liquid solution of CNTs and laser light is launched into the MMI device. CNTs solutions using water and methanol as solvents were tested. In addition, the use of a polymer dispersant polyvinylpyrrolidone (PVP) in the CNTs solutions was also studied. We found that the laser-induced deposition of CNTs performed in water-based solutions generates non-uniform deposits. On the other hand, the laser-induced deposition performed with methanol solutions generates uniform deposits over the fiber tip when no PVP is used and deposition at the center of the fiber when PVP is present in the CNTs solution. The results show the crucial role of the solvent on the spatial features of the laser-induced deposition process. Finally, we register and study the reflection spectra of the as-fabricated CNTs deposited MMI devices.
关键词： multimode interference,carbon nanotubes,laser-induced deposition,optical fibers
更新于2025-09-11 14:15:04
-
Nanoparticle and solution doping for efficient holmium fiber lasers
摘要： Efficient holmium fiber lasers have been studied as attractive laser sources operating around 2.1 μm. We report on holmium-doped silica fibers prepared by the modified chemical vapor deposition in combination with either a solution-doping method or a nanoparticle-doping method. A set of 15 fibers with various compositions was characterized and compared with respect to their fluorescence lifetime, laser slope efficiency and laser threshold. This set of fibers in wide concentration ranges allowed us to assess reliably the influence of material composition and the influence of doping method. The best-performance fibers exhibited slope efficiency 83.1%, laser threshold 155 mW and a record value of upper laser level lifetime of 1.35 ms. These results were achieved in fibers with holmium concentration lower than 800 molar ppm and Al/Ho molar ratio greater than 70. Significant differences between fibers prepared by solution doping and nanoparticle doping were not observed. The behavior of Al2O3 nanoparticles during fiber preparation is discussed in details.
关键词： infrared fibers.,Fiber laser
更新于2025-09-11 14:15:04
-
Space division multiplexing in standard multi-mode optical fibers based on speckle pattern classification
摘要： In optical communications the transmission bandwidth of single mode optical fibers is almost fully exploited. To further increase the capacity of a telecommunication link, multiplexing techniques can be applied across 5 physical dimensions: amplitude, quadrature, polarization, frequency and space, with all but the latter being nearly exhausted. We experimentally demonstrate the feasibility of an original space division multiplexing technique based on the classification of speckle patterns measured at the fiber’s output. By coupling multiple optical signals into a standard multimode optical fiber, speckle patterns arise at the fiber’s end facet. This is due to quasi-random interference between the excited modes of propagation. We show how these patterns depend on the parameters of the optical signal beams and the fiber length. Classification of the speckle patterns allows the detection of the independent signals: we can detect the state (i.e. on or off) of different beams that are multiplexed in the fiber. Our results show that the proposed space division multiplexing on standard multimode fibers is robust to mode-mixing and polarization scrambling effects.
关键词： space division multiplexing,mode-mixing,speckle patterns,polarization scrambling,optical communications,multimode optical fibers
更新于2025-09-11 14:15:04
-
Hearing the Sounds of Aquatic Life Using Optical Fiber Micro-tip based Hydrophone
摘要： For marine bioacoustics applications, the sounds by aquatic animals must be recorded with high precision and minimal noise in order to extract valuable information. For such marine applications, we propose and demonstrate an optical fiber micro-tip based hydrophone. The hydrophone design consists of an extrinsic Fabry-Perot interferometer which utilizes fiber micro-tip and processed aluminium foil as two partially reflecting mirrors. The packaged optical fiber hydrophone of dimensions 1.4 cm x 1.4 cm x 2 cm, with a microtip diameter of 31.23 μm and natural rubber diaphragm of 6 mm diameter shows a high sensitivity of 8.94 nm/mPa or -41.42 dB re 1 nm/μPa at 1 KHz. The hydrophone shows an excellent signal to noise ratio and the noise-limited minimum detectable pressure is as low as 0.388 μPa/√Hz at 1 KHz. The linear working range of the hydrophone is 0-3950 Hz. The experimental results show that the proposed optical fiber hydrophone can very accurately detect the click trains produced by dolphins for echolocation. Further, depending on the applications, the performance parameters of the proposed hydrophone can be tailored by changing the diaphragm thickness and diameter, thus opening a new platform to study marine environment.
关键词： Optical fibers,Acoustic signal detection,Underwater Optical equipment,Underwater acoustics,fiber sensors
更新于2025-09-11 14:15:04
-
Recycled fiber derived carbon dispersed Ag nanoparticles as high-performance catalyst for 4-nitrophenol reduction and substrate for surface-enhanced Raman scattering
摘要： Hydroxyl-rich waste fibers have been utilized as support to synthesize paper derived monodispersed Ag composites. We utilized the one-step thermal reduction and carbonization method to synthesize a meso-pore carbon frame with mono-dispersed silver nanoparticles (Ag@C). The Ag@C showed excellent catalytic activity in 4-nitrophenol reduction reactions attributing to their well dispersed silver nanoparticles and high surface area. The Ag@C catalyst could be recycled for ten times without significant loss of its catalytic activity. Furthermore, the Ag@C could be used as a Surface-enhanced Raman scattering (SERS) substrate, and the SERS signals strength were shown to be seven times higher than unloaded carbon membrane. The results clearly indicated that the Ag nanoparticle-loaded recycled fibers exhibited SERS activity, rendering it an excellent SERS substrate for practical applications. The efficient utilization of the widely accessible waste fibers from paper-making industry could provide a sustainable feature of this work to reduce manufacturing cost and contribute it to be an environment-friendly bifunctional material.
关键词： SERS,Composites,Catalyst,Ag nanoparticles,Recycled fibers
更新于2025-09-11 14:15:04