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In this paper, we demonstrate a 2μm switchable single-longitudinal-mode dual-wavelength fiber laser based on composite cavity and a core-offset structure. The fiber laser is switchable, power-equalized and operating in single-longitudinal-mode.
A magnetic field sensor based on twisted single mode fiber and magnetic fluid (MF) is proposed and demonstrated. The sensor consists of two twisted points on a single mode fiber introduced by flame-heated and rotation treatment. Cladding modes are excited at the first twisted point and part of them are coupled back to the fiber core at the second twisted point, forming an inline Mach-Zehnder interferometer...
Time-Reversal (TR) technology is used in a Microwave Power Transmission (MPT) system with multiple unknown-position targets. In the TR-MPT system, the Time-Reversal Mirror (TRM) array receives detecting signals emitted from the targets and re-emits the time-reversed one convoluted with high energy electromagnetic waves, and then the electromagnetic wave energies are focused on the targets. Three cases...
We propose a novel demodulation method for fiber acoustic sensor based on ripple spectrum, which comes from wavelength sweeping while spectrum varying with acoustic wave. Acoustic signal is recovered from the ripple spectrum and transformed to time domain by sweeping speed. Feasibility is demonstrated by both LPG and FPI sensor head.
A diaphragm based Michelson interferometric fiber-optic acoustic sensor based on symmetric 3×3 coupler is demonstrated in this paper. An ellipse fitting differential cross multiplication algorithm is proposed for signal interrogating. Experimental results show that a minimum detectable pressure (MDP) level of ∼500 μPa/Hz1/2 is obtained.
A low frequency fiber acoustic sensor based on the transduction of 10nm thickness graphene diaphragm has been experimentally demonstrated. The ultra thin graphene diaphragm is used as a reflecting surface to form an extrinsic Fabry-Perot interferometer. The diameter of the graphene diaphragm is selected as 125 pm, thus the resonant frequency of 25958Hz is obtained. The sensitivity of the acoustic...
Object detection is an important yet challenging task in video understanding & analysis, where one major challenge lies in the proper balance between two contradictive factors: detection accuracy and detection speed. In this paper, we propose a new adaptive patch-of-interest composition approach for boosting both the accuracy and speed for object detection. The proposed approach first extracts...
III-nitride based nanostructures have gained interest as nanoscale light sources in the UV to visible wavelengths. Here we present a top-down approach to enable vertical, high aspect ratio III-nitride-based nanowires with controllable height, pitch, and diameter. Additionally, through the use of orientation-dependent etch rate measurements, the cross-sections of such nanostructures can be predicted...
In order to simply and effectively extract important feature information and improve the accuracy of microscopic image recognition of Chinese Herbal Medicine (CHM), a kind of microscopic image enhancement technique of CHM based on fuzzy sets is put forward. Fuzzy set describes the vague degree of information, which study the different objects belong to the same class of membership relations. Implementation...
A semiconductor laser with distributed feedbacks from a novel fiber random grating is perturbed to emit chaotically. The time delay signature of the chaotic output is suppressed with the largest extent to date.
This paper considers the emergency backup in an inter-datacenter (inter-DC) network whose topology is time-variant due to the progress of a disaster. We first transform the dynamic backup into a static flow problem through building a variable time-expanded network (V-TEN). Then, by considering both data utility and resource cost, we formulate an optimization to maximize the backup profit and leverage...
In order to filter out microscopic image of Chinese herbal medicines (CHM) which is exposed by impulse noise pollution in the process of collection and access, and improve the efficiency and accuracy of the images in the follow-up detection and identification process, an algorithm of impulse noise detection and the two-step filtering using improved Pulse Coupled Neural Networks (PCNN) and morphology...
The purpose of this paper is to study the deadline assignment for the segments of tasks on multiprocessor systems. Each task consists of sequential and parallel segments. A parallel segment needing more computation power can be parallelized and executed on more than one processor simultaneously. When a task is only executed on a unique processor, the overall execution time will be more than its deadline...
We address the problem of position control of micro-chips (chiplets) immersed in dielectric fluid. An electric field, shaped by controlling the voltages of spiral shaped electrodes, is used to reliably and accurately transport and position chiplets using dielectrophoretic forces. A lumped, capacitive based (nonlinear) motion model is used to generate an open loop control policy. The open loop policy...
Two novel configurations of multi-parameter fiber-optic sensing systems based on the fiber random grating are reported. The fiber random grating is fabricated through femtosecond laser induced refractive index modification over a 10cm standard telecom single mode fiber. In one configuration, the reflective spectrum of the fiber random grating is directly detected and a wavelength-division spectral...
A highly sensitive twist sensor without temperature cross sensitivity based on tapered single mode-thin core-single mode fiber offset structure is proposed and experimentally demonstrated. The two parameters mentioned above can be measured simultaneously without cross sensitivity. The twist sensitivity of 0.12dB/° is achieved by tracking power variation of the resonant wavelength, and the wavelength...
Femtosecond infrared (fs-IR) laser written fiber Bragg gratings (FBGs), have demonstrated great potential for extreme sensing. Such conditions are inherent in advanced gas turbine engines under development to reduce greenhouse gas emissions; and the ability to measure temperature gradients in these harsh environments is currently limited by the lack of sensors and controls capable of withstanding...
A high impedance surface electromagnetic band gap (HIS-EBG) structure is proposed so as to design the core of a Hankel Inward Leaky Wave (HILW) antenna. HIS-EBG structure is expected to mimic a Perfect Magnetic Conductor (PMC), which is an alternative solution to the core absorber in order to generate properly the focusing spot with the HILW antenna. The proposed HIS-EBG structure is made of a mushroom-like...
A 2μm novel dual-wavelength single-longitudinal-mode (SLM) fiber laser based on saturable absorber and self-injection locking which can ensure SLM operating stable is reported. The proposed configuration has ingenious and compact structure, and reliable performance.
We proposed a novel scheme for simultaneous measuring strain and temperature with high sensitivity by introducing higher-order modes interference in a single-mode-twisted-multimode-single-mode(STMS) structure. The strain and temperature sensitivity reach −14.2 pm/μs and 28.61 pm/°C, respectively.
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