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- 摘要
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Novel OSNR Measurement Techniques Based on Optical Spectrum Analysis and their Application to Coherent-Detection Systems
摘要： We discuss and review in-service Optical-Signal-to-Noise-Ratio measurement techniques with a focus on methods relying on optical spectrum analysis. We briefly review the OSNR definition and the measurement procedure employed in early multi-wavelength systems with in-line amplification, and present in detail the development of the spectrum-based OSNR measurement methods to account for polarized, filtered DWDM signals, and further still, to the current generation of DWDM systems based on coherent detection. We present mathematical implementations for the measurement of polarized signals and their evolution to a reference-based method, suitable for measuring polarization-multiplexed signals independent of coherent transmission formats and receiver metrics. The performance of this reference-based technique is illustrated in a wide range of coherent transmission use cases, thus demonstrating its tolerance to fiber non-linearity induced spectral deformation of the signal. We also explain and demonstrate the ability of this technique to discriminate the amplified spontaneous emission noise due to in-line amplifiers from “Gaussian-like” noise generated in a non-linear operating regime. Finally, we present an extension of this OSNR measurement technique for links where in-line filtering causes significant spectral deformations of the signal and we show how it can be applied to troubleshooting and maintenance-monitoring use cases. The OSNR measurement statistics across all test conditions indicate accuracy levels suitable for use in deployed DWDM networks with ROADMs and coherent transponders.
关键词： signal to noise ratio,optical receivers,optical fiber testing,Optical fiber communication
更新于2025-09-23 15:21:21
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Recent progress in all-fiber non-Gaussian optical beam shaping technologies
摘要： Rapid development of fiber lasers are being followed by wide ranges of applications in laser processing technologies. One of the key parameters to determine the laser-matter interaction is beam shape and there have been intense research activities on beam shaping using bulk-optics. However, fiber optic solutions would take clear advantages over bulk-optics especially for fiber laser sources in terms of the beam conversion efficiency, the throughput power, and the compact footprint. In this article, all-fiber optical beam shaping technologies are reviewed and they are categorized as the phase front modification on the fiber facet, the surface plasmonics on fiber, all-fiber Fourier transformation, and multimode interference. Their physical principles, beam shaping capability, and some of the novel applications are explained
关键词： Phase front engineering,Laser beam,Surface plasmon polariton,Beam Shaping,Multimode Interference,Fourier Transform,Fiber Optics,Single mode optical fiber
更新于2025-09-23 15:21:21
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Distributed Measurement of Polarization Mode Coupling in Polarization Maintaining Fibers Using Microwave Photonic Filter Technique
摘要： Polarization mode coupling (PMC) is a detrimental effect that limits the polarization maintaining performance of polarization maintaining fibers (PMF). In this paper, we propose and demonstrate a novel method based on a principle similar to that of a microwave photonic filter (MPF) for the PMC distribution measurement. By regarding the PMF with PMC taking place as an MPF and measuring its transfer function in frequency domain, we are able to identify the intensities and locations of PMC events along PMFs. After detailed theoretical analysis and numerical simulations, validation experiments have been conducted on four PMF segments with rotational splicing between each other to manually generate PMCs. The measurement results of PMC positions and strengths are in accordance with the preset values. With a frequency scanning step of 16 MHz and a range of 14.4 GHz, such method can achieve a spatial resolution of 30 m and a measurement range of 27 km. The proposed method is suitable for the measurement of PMCs along PMFs up to tens of kilometers.
关键词： microwave filters,optical fibers,microwave photonics,Optical fiber polarization
更新于2025-09-23 15:21:21
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Recent Advances in Brillouin Optical Correlation-Domain Reflectometry
摘要： Distributed ?ber-optic sensing based on Brillouin scattering has been extensively studied and many con?gurations have been developed so far. In this paper, we review the recent advances in Brillouin optical correlation-domain re?ectometry (BOCDR), which is known as a unique technique with intrinsic single-end accessibility, high spatial resolution, and cost ef?ciency. We brie?y discuss the advantages and disadvantages of BOCDR over other Brillouin-based distributed sensing techniques, and present the fundamental principle and properties of BOCDR with some special schemes for enhancing the performance. We also describe the recent development of a high-speed con?guration of BOCDR (slope-assisted BOCDR), which offers a beyond-nominal-resolution detectability. The paper is summarized with some future prospects.
关键词： Brillouin scattering,optical fiber sensing,temperature sensing,distributed sensing,structural health monitoring,optical correlation-domain reflectometry,strain sensing,nonlinear optics
更新于2025-09-23 15:21:21
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Live E. coli bacteria label-free sensing using a microcavity in-line Mach-Zehnder interferometer
摘要： The paper presents the first study to date on selective label-free biosensing with a microcavity in-line Mach-Zehnder interferometer induced in an optical fiber. The sensing structures were fabricated in a single-mode fiber by femtosecond laser micromachining. In contrast to other studies of this sensing scheme, where only the sensitivity to refractive index changes in the cavity was investigated, this research used chemical surface treatment of the sensor to ensure detection specificity. Immobilized MS2 bacteriophages were applied as recognition elements specifically targeting live E. coli C3000 bacteria. It is shown that the sensor allows for real-time monitoring of biological phenomena taking place on the surface of the microcavity. The developed biosensor exhibits ultrahigh refractive index sensitivity of 15,000 nm/RIU and is capable of detecting live E. coli bacteria concentrations as low as 100 colony forming units (CFU)/mL in liquid volume as low as picoliters.
关键词： label-free biosensing,E. coli C3000 bacteria,refractive index sensitivity,MS2 bacteriophages,femtosecond laser micromachining,microcavity in-line Mach-Zehnder interferometer,optical fiber
更新于2025-09-23 15:21:21
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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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Polymer Fiber Optic Sensors – A Mini Review of their Synthesis and Applications
摘要： Fiber optic sensors (FOSs) are optical fiber based sensing devices that have been widely used to detect physical, chemical and biological parameters. Polymer optical fibers (POFs), an important type of optical fibers, have been stifled their talents in the field of optical sensing due to the overwhelming popularity of glass optical fibers (GOFs). The unique physical and chemical properties of POFs start attracting interests to be utilized in the fabrication of high performance sensors in recent years. This article reviews the recent progress of POFs based FOSs. In particular, the article will focus on novel techniques implemented on the POF sensor fabrication, including monolayer graphene, evanescent wave absorption, localized surface plasmon resonance and fiber Bragg grating.
关键词： Localized surface plasmon resonance,Fiber Bragg gratings,Evanescent wave,Microstructured polymer optical fiber,Polymer fiber optic sensor
更新于2025-09-23 15:21:01
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[IEEE 2020 Moscow Workshop on Electronic and Networking Technologies (MWENT) - Moscow, Russia (2020.3.11-2020.3.13)] 2020 Moscow Workshop on Electronic and Networking Technologies (MWENT) - Laser Optical Fiber Systems Prospects Use Evaluation
摘要： The paper considers the various fiber-optic devices, systems and its components improvement issues. The fiber-optic information-measuring systems structure questions on the fiber-optic devices basis are considered. The various fiber-optic devices, systems and its components dignity and benefits are shown. It is shown that fiber-optic laser measuring systems can be successfully used to measure pressure, temperature, linear and angular micro-displacements, vibration parameters, mechanical tensions, etc.
关键词： fiber optical device,information and measurement system,measurement,optical fiber,laser
更新于2025-09-23 15:21:01
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Online fire protection technology based on fiber optic gas sensor
摘要： In recent years, the production safety has been paid by a lot of attention. Although the total number of accidents in production safety has shown a downward trend, the serious accidents occur frequently and seriously. The prediction and early warning of spontaneous combustion in coal mines mainly adopts the method of gas index analysis and prediction. The traditional trace gas detection equipment used in spontaneous combustion is mainly chromatographic analysis system, which has some problems such as complicated equipment, complicated operation, slow analysis speed and inability to realize on-line monitoring. The main purpose of this study is to develop a fire risk distribution determination system based on multi-sensor information fusion technology, which is aimed at assisting fire monitoring, fire emergency management, and fire rescue. After using the information from different sensors, the system can give an effective alarm to the fire and can provide the danger degree distribution information of different areas in the building. Based on the development status of fire safety, especially the demand of fire safety for gas detection technology, the tunable laser spectroscopy technology is proposed to solve the demand problem of gas sensing products urgently needed for major fire disasters.
关键词： Optical Fiber,Fire Safety,Optical Fiber Methane Sensor,Multicomponent Gas Detection
更新于2025-09-23 15:21:01
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[IEEE 2019 IEEE International Electron Devices Meeting (IEDM) - San Francisco, CA, USA (2019.12.7-2019.12.11)] 2019 IEEE International Electron Devices Meeting (IEDM) - Demonstration of BEOL-compatible ferroelectric Hf <sub/>0.5</sub> Zr <sub/>0.5</sub> O <sub/>2</sub> scaled FeRAM co-integrated with 130nm CMOS for embedded NVM applications
摘要： We present a phase mask inscription technique with two beam interferometry using a lateral nonhomogeneous beam splitter to create gratings with nonhomogeneous periods, the so-called chirped fiber Bragg gratings. Inscription experiments with deep ultraviolet excimer and femtosecond laser sources reveal how this inscription method depends on the coherence properties of the inscription laser. Nonhomogeneous beam splitters are shown to provide a method to generate chirped fiber Bragg gratings with great wavelength versatility, even with the ultraviolet femtosecond laser.
关键词： Femtosecond laser,optical fiber filters,two-beam interferometry,fiber Bragg gratings
更新于2025-09-23 15:21:01