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- 摘要
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- 实验方案
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Estimation of Crack Mouth Opening Displacement in Concrete Using Optical Fiber Sensors
摘要： Concrete is a multi-phase composite material and used widely in construction industry because of high compressive strength and low cost. Its limited tensile strength makes it prone to cracking. Important parameters like characteristic length, fracture energy Gf critical crack width WC are used to understand cracks in concrete. The crack width is estimated either as crack mouth opening displacement (CMOD/COD) or as crack tip opening displacement (CTOD). Several optical and non-optical methods can provide information about crack presence but do not provide information on crack opening and crack width which are important from considerations of durability. To this end we present our research results in three point bend tests on pre-notched concrete samples (M-20 composition) using (a) Intensity based plastic optic fiber (POF) using phase difference measurement method (b) Fiber Bragg grating (FBG) method. The CMOD estimation and relative sensitivity of these methods will be presented.
关键词： Phase difference method,UTM,Crack mouth opening displacement,FBGs,Three point bend specimens,Prenotched concrete,Plastic optical fiber
更新于2025-09-11 14:15:04
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Integrated Metamaterial Interfaces for Self-Aligned Fiber-to-Chip Coupling in Volume Manufacturing
摘要： Improving the scalability and cost efficiency of photonic packaging is central to fulfilling the silicon photonic promise of low-cost devices with unprecedented optical complexity. A key enabler towards this goal is an efficient, large-mode, integrated fiber coupler and mode converter. Using standard fiber modes at fiber-to-chip junctions avoids expensive in-fiber mode conversion and relaxes alignment tolerances for low-cost assembly and improved reliability. Metamaterial waveguides, also called subwavelength gratings, are particularly useful for such structures. They provide unmatched design flexibility and, counter-intuitively, are more forgiving to fabrication tolerances than solid-core waveguides. Here, we summarize our work on interfacing self-aligned, standard cleaved fibers to rectangular Si routing waveguides. Fiber V-grooves are integrated on chip with metamaterial converters embedded in suspended oxide membranes to prevent coupler-mode leakage to the substrate. We show optical results from first integration of V-grooves with metamaterial converters to commercial structures fabricated in 300 mm CMOS production facilities. We demonstrate a peak transmission of -0.7 dB on the TE polarization and -1.4 dB on the TM polarization with a respective spectral roll-off of 0.3 and 0.4 dB over the 60 nm bandwidth measured.
关键词： photonic bandgap materials,packaging,optical fiber communication,integrated optoelectronics
更新于2025-09-11 14:15:04
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[IEEE 2018 14th International Conference on Advanced Trends in Radioelecrtronics, Telecommunications and Computer Engineering (TCSET) - Lviv-Slavske (2018.2.20-2018.2.24)] 2018 14th International Conference on Advanced Trends in Radioelecrtronics, Telecommunications and Computer Engineering (TCSET) - Special features of structural design for a fiber-optic microdisplacement transducer
摘要： In this paper, we describe the design of a fiber-optic pressure sensor and the principle of operation. The principle of operation of fiber-optic pressure sensors is as follows. From the radiation source, the light flux along the supply optical fibers is directed to the side of the membrane at an angle, the value of which is selected from the condition of ensuring the maximum sensitivity of the conversion and the depth of modulation of the optical signal. Under the influence of controlled pressure, the membrane deflects, and in the central part the gap between the membrane and the bevelled ends of the optical fibers will be less than the initial value X0. As a result, the reflectivity for electromagnetic waves in the region of the chamfered ends of the optical fibers changes, and accordingly the intensity of the light flux reflected at an angle from the given region, which carries information about the measured pressure and arrives along the diverting optical fibers to the radiation receiver, changes. The optical system of a fiber-optic pressure sensor is calculated, which consists in determining a number of fiber-optic micro-displacement design parameters the MathCAD transducer. Mathematical modeling environment was carried out. Based on the results of mathematical modeling, a new design solution has been proposed for a fiber-optic micro-displacement transducer, in which the incoming and outgoing optical fibers are cut off and located at a calculated angle. The function of converting a fiber-optic micro-displacement transducer is defined. The selected parameters ensure the fulfillment of the conditions for reducing the temperature and dynamic errors, increasing the sensitivity of the optical signal conversion while reducing the mass-dimensional characteristics of the fiber-optic pressure sensor.
关键词： silicon membrane,transformation function,optical fiber,fiber-optic sensor,fiber-optic transducer
更新于2025-09-10 09:29:36
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Research on high resolution fiber Bragg grating sensing technology based on high speed parallel sampling
摘要： The high resolution fiber Bragg sensing system based on high speed parallel sampling technology is proposed. According to the Rayleigh criterion, it is generally believed that the number of the measured data of the fiber grating reflection spectrum is limited to the resolution of the wavelength measurement device. So, in order to achieve high spectral resolution, high resolution wavelength measurement devices, at the same time, to achieve small variations of the transmission wavelength of the Fabry–Perot (FP) filter, the high bit digital-to-analog converter (DAC) was adopted to generates small step drive voltages, these will greatly increase the cost of the system. However, in this paper, the fiber Bragg sensing system with the low resolution FP filter and low bit DAC achieves the high resolution wavelength measurement by using the high speed parallel sampling. In addition, the resolution of wavelength in fiber grating sensing system is analyzed theoretically.
关键词： Parallel sampling technology,Wavelength resolution,Fiber Bragg grating,Optical fiber sensing
更新于2025-09-10 09:29:36
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[IEEE 2018 IEEE International Instrumentation and Measurement Technology Conference (I2MTC ) - Houston, TX, USA (2018.5.14-2018.5.17)] 2018 IEEE International Instrumentation and Measurement Technology Conference (I2MTC) - Experimental evaluation of low-cost interrogation techniques for FBG sensors
摘要： In this paper, the experimental investigation of two simple, cost-effective interrogation techniques based on optical power measurement for fiber Bragg gratings (FBG) sensors are presented. The first technique proposed employs each channel of a CWDM demultiplexer as an edge filter to modulate the optical power reflected by each sensing FBG, allowing for an array of FBG sensors to be interrogated simultaneously, sharing the same broadband light source (BLS) and interrogation system. In the second technique, the optical power reflected by a single sensing FBG is modulated directly by the transmission spectrum of the BLS, allowing for a simpler interrogation system. Both techniques rely on a compact, low-cost optoelectronic circuit developed for the acquisition and measurement of the optical signals. With resolutions of up to 1.26 pm for a mechanical strain sensor, or an equivalent 0.09 oC for a temperature sensor, experimental results show that both techniques are accurate, reliable, and suitable for applications where the only requirement is the monitoring of the spectral position of the Bragg wavelength (λB) of the FBG sensors, replacing more expensive, general-purpose FBG interrogators available in the market. Since FBGs are passive, lightweight, and provide dielectric insulation, the proposed techniques are suitable for temperature or mechanical strain measurements in hostile environments in which the use of conventional sensors must be avoided, such as in high voltage power lines and cables, and explosive atmospheres.
关键词： fiber Bragg gratings,temperature measurement,temperature sensors,optical fiber sensors
更新于2025-09-10 09:29:36
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Rapid Prototyping of a Micromotor with an Optical Rotary Encoder
摘要： This study proposed a rapid prototyping fabrication method for micromotors that allowed us to develop both 1 mm and 1.5 mm diameter permanent-magnet synchronous motors (PMSMs) with an optical rotary encoder. First, an integrated electroforming method was proposed for combining stator housing and flexible print circuit (FPC) coils to ease the manufacturing and assembly of micromotor components. This is particularly useful in the production of prototypes or small volumes of units. Second, an optical encoder was used to detect the rotational angle by means of a reflective code disk, an optical fiber, and a photo-detector. The micromotor was built with a code disk and an optical fiber. The code disk was designed to match the optical fiber and was made by photolithography and sputtering. Both the 1 mm and 1.5 mm diameter motors successfully achieved a rotational speed over 20,000 RPM and due to a 50 μm diameter optical fiber core, the encoders showed a resolution of 12 and 18 pulses per revolution (PPR), respectively.
关键词： micromotor,optical fiber,permanent-magnet synchronous motors,flexible print circuit,optical encoder,electroforming,rapid prototyping
更新于2025-09-10 09:29:36
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Digital Domain Power Division Multiplexed Dual Polarization Coherent Optical OFDM Transmission
摘要： Capacity is the eternal pursuit for communication systems due to the overwhelming demand of bandwidth hungry applications. As the backbone infrastructure of modern communication networks, the optical fiber transmission system undergoes a significant capacity growth over decades by exploiting available physical dimensions (time, frequency, quadrature, polarization and space) of the optical carrier for multiplexing. For each dimension, stringent orthogonality must be guaranteed for perfect separation of independent multiplexed signals. To catch up with the ever-increasing capacity requirement, it is therefore interesting and important to develop new multiplexing methodologies relaxing the orthogonal constraint thus achieving better spectral efficiency and more flexibility of frequency reuse. Inspired by the idea of non-orthogonal multiple access (NOMA) scheme, here we propose a digital domain power division multiplexed (PDM) transmission technology which is fully compatible with current dual polarization (DP) coherent optical communication system. The coherent optical orthogonal frequency division multiplexing (CO-OFDM) modulation has been employed owing to its great superiority on high spectral efficiency, flexible coding, ease of channel estimation and robustness against fiber dispersion. And a PDM-DP-CO-OFDM system has been theoretically and experimentally demonstrated with 100 Gb/s wavelength division multiplexing (WDM) transmission over 1440 km standard single mode fibers (SSMFs).
关键词： spectral efficiency,digital domain power division multiplexing,non-orthogonal multiple access,coherent optical OFDM,optical fiber transmission
更新于2025-09-10 09:29:36
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[IEEE 2018 20th International Conference on Transparent Optical Networks (ICTON) - Bucharest (2018.7.1-2018.7.5)] 2018 20th International Conference on Transparent Optical Networks (ICTON) - Machine Learning Based Optimal Modulation Format Prediction for Physical Layer Network Planning
摘要： Physical layer network design and planning process is a cumbersome one. It includes laying out all possible combinations of modulation formats, fiber types, forward error correction codes, channel spacing, etc., conducting exhaustive simulations and lab experiments to come up with carefully tuned engineering rules, and finally using these approximate models to propose transmission feasibility. Besides being cumbersome, there are two fundamental issues in conventional network planning approach, firstly it almost exclusively offers conservative design, leading to resource underutilization, and secondly it’s not scalable – neither from planning viewpoint nor computationally – to next-generation highly granular and flexible networks. Machine learning, an artificial intelligence toolset, may be applied to solve aforementioned issues by allowing data-driven model development, and consequent transmission quality prediction. While network planning is an extensive topic, in this paper, we focus on neural network based modulation format classification, autonomously identifying best possible modulation format for a given link configuration.
关键词： machine learning,analytics,communication networks,optimization,optical fiber communications
更新于2025-09-10 09:29:36
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Effect of polarization dependent loss on the quality of transmitted polarization entanglement
摘要： Quantum networking brings together several diverse research areas, such as fiber-optic communication, quantum optics, and quantum information, to achieve capabilities in security, secret sharing, and authentication which are unavailable classically. The development of practical fiber-based quantum networks requires an understanding of the reach, rates, and quality of the entanglement of distributed quantum states. Here, we present a theoretical model describing how the magnitude and orientation of polarization dependent loss (PDL), a common impairment in fiber-optic networks, affects the entanglement quality of distributed quantum states. Furthermore, we theoretically characterize how PDL in one fiber channel can be optimally applied in order to nonlocally compensate for the PDL present in another channel. We present experimental results which verify our theoretical model.
关键词： Optical fiber communication,quantum entanglement
更新于2025-09-10 09:29:36
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Real-time signal processing for sub-THz range grating-based distributed fiber sensing
摘要： Distributed optical fiber sensors are an increasingly utilized method of gathering distributed strain and temperature data. However, the large amount of data they generate presents a challenge that limits their use in real-time, in situ applications. This article describes a parallel and pipelined computing architecture that accelerates the signal-processing speed of sub-terahertz fiber sensor arrays, maintaining high spatial resolution while allowing for expanded use of real-time sensing and control applications. The computing architecture described was successfully implemented in a field programmable gate array chip. The signal processing for the entire array takes only 12 system clock cycles. In addition, this design removes the necessity of storing any raw or intermediate data.
关键词： distributed optical fiber sensors,real-time signal processing,sub-THz range,FPGA,grating-based
更新于2025-09-10 09:29:36