- 标题
- 摘要
- 关键词
- 实验方案
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Investigation of narrow band random fiber ring laser based on random phase-shift Bragg grating
摘要： A random ?ber laser based on a 25 mm long random phase-shift ?ber Bragg grating with a ring cavity is experimentally demonstrated in this paper. The random phase-shift grating is fabricated with the beam-scanning method in a single-mode ?ber. The random feedback and light localization are achieved by introducing 20 phase-shift points with random amplitudes along the grating length. A narrow band single-wavelength random ?ber laser with the 3 dB bandwidth of 0.44 pm is realized with a 980 nm laser pumping at 130 mW. The optical signal-to-noise ratio up to 55 dB is obtained at the same pump power. The pump threshold is only 21.8 mW. The number of emitted wavelengths is changeable by adjusting the pump power. The lasing wavelength near 1549.96 nm presents a maximum ?uctuation range of only 1.1 pm over time. With the random grating exposed to water, the mode competition is suppressed and the laser can be operated at more stable single-wavelength mode.
关键词： Laser mode,Ring cavity,Grating,Optical ?ber laser
更新于2025-11-28 14:24:03
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Study on a high-temperature optical fiber F–P acceleration sensing system based on MEMS
摘要： Vibration measurement at high temperature is of great signi?cance to monitoring the operation of major projects and mechanical equipment. As the temperature resistance of electrical vibration sensors is usually below 600 °C, it cannot meet the requirements of some high-temperature measuring conditions. This paper studies a high-temperature Fabry–Perot (F–P) acceleration sensing system with general single-mode ?ber. A high-temperature sensitive diaphragm is machined based on micro-electromechanical system (MEMS) technology and it is combined with the ?ber microstructure to enable the sensing probe to be packaged under high temperatures. According to the temperature characteristic of the length of the F–P cavity, a signal demodulation system was proposed based on the rapid automatic tracking of the quiescent operation point. The complete optical ?ber F–P acceleration sensing system conducted real-time vibration detection of high temperature casting in the foundry factory. The experimental result indicates that the optical ?ber high-temperature acceleration sensor showed a better vibration response in the working frequency of 100–1000 Hz and the relative error of the frequency measurement is less than 1.56% under normal temperatures and a high temperature of 800 °C.
关键词： Optical ?ber F–P,High-temperature,Acceleration sensor,Tunable laser source,MEMS
更新于2025-11-28 14:23:57
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Tilted Fiber Bragg Grating Sensor Using Chemical Plating of a Palladium Membrane for the Detection of Hydrogen Leakage
摘要： A tilted ?ber Bragg grating (TFBG) hydrogen sensor coated with a palladium (Pd) membrane by the electroless plating method is proposed in this paper. A uniform layer of Pd metal is fabricated in aqueous solutions by the chemical coating method, which is used as the sensitive element to detect the change of the surrounding refractive index (SRI) caused by hydrogen absorption. The change in SRI causes an unsynchronized change of the cladding modes and the Bragg peak in the TFBG transmission spectrum, thereby eliminating the cross-sensitivity due to membrane expansion and is able to simultaneously monitor the presence of cracks in the pipe, as well as the hydrogen leakage. By subtracting the wavelength shift caused by ?ber expansion, the change of SRI, i.e., the information from the H2 level, can be separately obtained. The drifted wavelength is measured for the H2 concentration below the hydrogen explosion limit between 1% and 4%. The chemical-based coating has the advantages of a low cost, a simple operation, and being suitable for coating on long ?ber structures. The proposed sensor is able to detect the H2 signal in 5 min at a 1% H2 concentration. The proposed sensor is proved to be able to monitor the hydrogen level without the cross-sensitivity of temperature variation and expansion strains, so could be a good candidate for security applications in industry.
关键词： electroless plating,tilted ?ber Bragg grating,optical ?ber hydrogen sensor,palladium membrane
更新于2025-09-23 15:22:29
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[IEEE 2019 IEEE 46th Photovoltaic Specialists Conference (PVSC) - Chicago, IL, USA (2019.6.16-2019.6.21)] 2019 IEEE 46th Photovoltaic Specialists Conference (PVSC) - Characterization of the Metallization Induced Recombination Losses in Industrial Silicon Solar Cells
摘要： We thoroughly analyze the requirements on the signal and idler state of polarizations (SOPs) for achieving maximum ampli?cation in phase-sensitive ampli?ers (PSAs). These requirements are described using a Jones-space description as well as a Stokes-space description. Our analysis includes the cases of polarization-diverse and vector PSAs, and in each type of PSA, we also consider the signal-degenerate and the non-degenerate schemes. We observe that the relation between the signal and idler SOPs to achieve maximum phase-sensitive (PS) ampli?cation can be described similarly in polarization-diverse and in vector PSAs. Moreover, both types of PSAs are polarization-dependent, which means that PSAs do require polarization-tracking schemes when being implemented in a realistic optical-transmission scenario. We therefore evaluate how polarization tracking of the signal and the idler SOPs can overcome the theoretical polarization dependence of both polarization-diverse and vector PSAs. We ?nd that only one polarization tracker for either the signal or idler SOP is necessary for achieving polarization-independent PS ampli?cation when considering the general case of dual-polarization (DP) modulated signals. This polarization tracker requires the control of three degrees of freedom which describe a general polarization rotation. For single-polarization (SP) modulated signals, the polarization tracker can rotate both the signal and the idler SOPs simultaneously which eliminates the need for splitting the signal and the idler before the PSA. Moreover, only two degrees of freedom for the polarization tracker are necessary in this case. When considering degenerate schemes, a polarization tracker with two degrees of freedom is suf?cient to achieve maximum PS ampli?cation of DP binary phase-shift keying (BPSK) signals in both vector and polarization diverse PSAs. For the case of SP-BPSK signals, a polarization-diverse PSA can perform polarization-independent ampli?cation by controlling the relative phase between the pumps, whereas a polarization tracker with only one degree of freedom is necessary in the case of vector PSAs.
关键词： parametric ampli?ers,Optical ?ber communication,phase-sensitive ampli?ers (PSAs),polarization
更新于2025-09-23 15:21:01
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Water Purification in Dark Conditions Using Photocatalytic Light-leakage Type Plastic Optical Fiber
摘要： In this study, we fabricated a device that can be used for water puri?cation in dark areas by combining a light-leakage type plastic optical ?ber with a photocatalyst. The light-leakage type ?ber was prepared by adding a scattering agent to the ?ber core, and the titanium dioxide photocatalyst was composited by a two-layer coating method. Photocatalytic decomposition of methylene blue was performed by introducing light into the ?ber without direct light irradiation.
关键词： Photocatalyst,Plastic optical ?ber,Water puri?cation
更新于2025-09-23 15:21:01
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[IEEE 2019 IEEE Sustainable Power and Energy Conference (iSPEC) - Beijing, China (2019.11.21-2019.11.23)] 2019 IEEE Sustainable Power and Energy Conference (iSPEC) - Evaluation of Harmonic Voltage Emission Level Considering Harmonic Impedance of Photovoltaic Side
摘要： We thoroughly analyze the requirements on the signal and idler state of polarizations (SOPs) for achieving maximum ampli?cation in phase-sensitive ampli?ers (PSAs). These requirements are described using a Jones-space description as well as a Stokes-space description. Our analysis includes the cases of polarization-diverse and vector PSAs, and in each type of PSA, we also consider the signal-degenerate and the non-degenerate schemes. We observe that the relation between the signal and idler SOPs to achieve maximum phase-sensitive (PS) ampli?cation can be described similarly in polarization-diverse and in vector PSAs. Moreover, both types of PSAs are polarization-dependent, which means that PSAs do require polarization-tracking schemes when being implemented in a realistic optical-transmission scenario. We therefore evaluate how polarization tracking of the signal and the idler SOPs can overcome the theoretical polarization dependence of both polarization-diverse and vector PSAs. We ?nd that only one polarization tracker for either the signal or idler SOP is necessary for achieving polarization-independent PS ampli?cation when considering the general case of dual-polarization (DP) modulated signals. This polarization tracker requires the control of three degrees of freedom which describe a general polarization rotation. For single-polarization (SP) modulated signals, the polarization tracker can rotate both the signal and the idler SOPs simultaneously which eliminates the need for splitting the signal and the idler before the PSA. Moreover, only two degrees of freedom for the polarization tracker are necessary in this case. When considering degenerate schemes, a polarization tracker with two degrees of freedom is suf?cient to achieve maximum PS ampli?cation of DP binary phase-shift keying (BPSK) signals in both vector and polarization diverse PSAs. For the case of SP-BPSK signals, a polarization-diverse PSA can perform polarization-independent ampli?cation by controlling the relative phase between the pumps, whereas a polarization tracker with only one degree of freedom is necessary in the case of vector PSAs.
关键词： polarization,Optical ?ber communication,phase-sensitive ampli?ers (PSAs),parametric ampli?ers
更新于2025-09-23 15:21:01
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Configurational entropy of optical bright similariton in tapered graded-index waveguide
摘要： Con?gurational entropy (CE) consists of a family of entropic measures of information used to describe the shape complexity of spatially-localized functions with respect to a set of parameters. We obtain the Differential Con?gurational Entropy (DCE) for similariton waves traveling in tapered graded-index optical waveguides modeled by a generalized nonlinear Schr?dinger equation. It is found that for similariton’s widths lying within a certain range, DCE attains minimum saturation values as the nonlinear wave evolves along the effective propagation variable ζ (t). In particular, saturation is achieved earlier for lower values of the width, which we show correspond to global minima of the DCE. Such low entropic values lead to minimum dispersion of momentum modes as the similariton waves propagate along tapered graded-index waveguides, and should be of importance in guiding their design.
关键词： Optical ?ber communications,Tapered graded-index waveguide,Bright similariton,Con?gurational entropy,Generalized nonlinear Schr?dinger equation
更新于2025-09-23 15:21:01
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Polymer Optical Fibers for Sensing
摘要： Sensing techniques based on optical ?bers are used in numerous key ?elds. For example, optical ?ber sensors are exploited in medical diagnostics, environmental monitoring, physical parameters detection, industrial applications, food safety, and security. In fact, optical ?ber sensors are used for their numerous capabilities, as for example when in the detection fast, portable, low-cost, small size, and/or rugged sensor systems are needed. In general, the optical ?ber for sensing applications can be a glass one, a specialty one, or a polymer one. Polymer optical ?bers (POFs) are especially advantageous due to their excellent ?exibility, easy manipulation, large diameter, resilience, and the fact that plastic is able to withstand smaller bend radii than glass. These POF sensors, intrinsic and extrinsic, combined with di?erent kinds of receptors can be directly connected to an online platform by interface software, allowing storing, analyzing, and displaying the sensor’s data, to realize low-cost biochemical sensors for several applications. In this work, two plasmonic POF sensors, one intrinsic and another one extrinsic, that can be used in biochemical applications are described.
关键词： optical sensors,intrinsic and extrinsic optical ?ber sensors,polymer optical ?bers,plasmonic sensors,biosensors
更新于2025-09-23 15:19:57
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[IEEE 2019 20th International Conference on Solid-State Sensors, Actuators and Microsystems & Eurosensors XXXIII (TRANSDUCERS & EUROSENSORS XXXIII) - Berlin, Germany (2019.6.23-2019.6.27)] 2019 20th International Conference on Solid-State Sensors, Actuators and Microsystems & Eurosensors XXXIII (TRANSDUCERS & EUROSENSORS XXXIII) - Infrared Photodetector with Copper Resonator in Silicon Nanohole Array
摘要： A highly linear broadband photonic-assisted analog-to-digital converter (ADC) based on high-frequency optical sampling utilizing a dual output Mach–Zehnder modulator operating with signal frequencies up to 50 GHz is presented. The pulses employed in the optical sampling were generated by a cavity-less pulse source operated at 10 GHz in preference to conventional mode-locked lasers. The optical sampling front-end greatly extends the operational frequency range of the Nyquist limited electronic digitization back-end. The performance of the sampling system is characterized with 7.1 effective number of bits (ENOBs) at 40 with 5 GHz fully accessible bandwidth, and greater than 99 dB·Hz2/3 spurious free dynamic range for the 30–40 GHz frequency range. Furthermore, more than 8 ENOB was achieved by reducing the effective bandwidth to 1 GHz with a digital ?lter, demonstrating the additional advantage of using a higher sampling rate compared to previous demonstrations. A new ?gure of merit of photonic-assisted sub-sampled ADCs is also presented accompanied with a comparison to previous implementations.
关键词： microwave photonics,optical data processing,sampling,Analog-digital conversion,detection,sub-sampling,optical ?ber communications
更新于2025-09-23 15:19:57
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High Sensitivity Refractive Index Sensor Based on the Excitation of Long-Range Surface Plasmon Polaritons in H-Shaped Optical Fiber
摘要： In this paper, we propose and numerically analyze a novel design for a high sensitivity refractive index (RI) sensor based on long-range surface plasmon resonance in H-shaped microstructured optical ?ber with symmetrical dielectric–metal–dielectric waveguide (DMDW). The in?uences of geometrical and optical characteristics of the DMDW on the sensor performance are investigated theoretically. A large RI analyte range from 1.33 to 1.39 is evaluated to study the sensing characteristics of the proposed structure. The obtained results show that the DMDW improves the coupling between the ?ber core mode and the plasmonic mode. The best con?guration shows 27 nm of full width at half maximum with a resolution close to 1.3 × 10?5 nm, a high sensitivity of 7540 nm/RIU and a ?gure of merit of 280 RIU?1. Additionally, the proposed device has potential for multi-analyte sensing and self-reference when dissimilar DMDWs are deposited on the inner walls of the side holes. The proposed sensor structure is simple and presents very competitive sensing parameters, which demonstrates that this device is a promising alternative and could be used in a wide range of application areas.
关键词： optical ?ber sensor,surface plasmon polariton (SPP),surface plasmon resonance,optical waveguides,refractive index (RI) sensor
更新于2025-09-23 15:19:57