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We propose a dual-parameter active fibre sensor based on a fibre ring laser using a single-mode-two-mode-single-mode (STS) fibre interferemeter and a four-mode FBG as the intracavity dual-parameter sensing element. The interferometric spectra of the STS are investigated with different core-offset parameters and few-mode fibre length. The highest LP11 mode excitation ratio is achieved with a 6µm core-offset...
By incorporating a 45° tilted grating in a fiber laser cavity with net anomalous dispersion, we have obtained stable soliton pulses with a high repetition. The laser could operate at high harmonics of the fundamental repetition frequency of the resonator (22.6 MHz) by properly adjusting the polarization controllers in the cavity. The highest achieved repetition rate is 2.2 GHz which corresponds to...
With the aid of broad-band visible light and colour shift keying(CSK), visible light communication (VLC) can construct high speed broadcast network in public scenarios. However, due to the broadcast property of light beam, the malicious eavesdroppers located in the same light beam as the legitimate receivers may capture the information. In order to improve the security of VLC systems, in this paper,...
The realization and characterization of an all-solid photonic bandgap fiber (AS-PBF) with a compact size of about 10 mm by means of fully infiltrating an ultraviolet (UV) curable polymer with a high refractive index of 1.515 into air holes of a photonic crystal fiber (PCF) is demonstrated. It appears to a high wavelength sensitivity of up to −4.034 nm/°C. Compared with conventional fluid filled PBFs,...
Compact traveling wave tubes (TWTs) operating at 220 GHz and 340 GHz respectively are being developed. The 220 GHz TWT is designed to produce 10 W output power and has achieved 0.2 W. The 340 GHz TWT is designed to produce 1 W output power and has not been demonstrated yet. This paper describes the development of the TWTs' components and some test results of two TWT prototypes.
We characterize a low-phase-noise Kerr frequency comb for carrying data channels. Results show pump wavelength detuning region grows slightly at higher pump power and the phase noise stays relatively unchanged over pump wavelength detuning region.
The control of Light velocity is theoretically and experimentally demonstrated in a θ-shaped microfiber resonator with coupled-resonator-induced transparency. By adjusting the structure parameters, group delays from −60ps to 200ps are achieved in the all-fiber resonator.
This paper designs and implements an embedded security gateway based on double-homed structure which composed of software and hardware parts. The core of hardware platform is based on two S3C6410 processors and one EP1C18F4620 FPGA. The software is based on reduced Linux kernel 3.0.1. The gateway uses Net-filter/IP-tables firewall, IPSec VPN and Network isolation technologies. And it can effectively...
Distribution Automation is one of the most important parts of the construction of Smart Grid. And the related standards are important for Smart Grid standard system. Modern power distribution network, which has three features including network grid, multi-connecting power supply and distribution automation, will strengthen the network connection. It improves the power supply service that less time...
Linear dielectric materials are ideal options for energy storage application due to the typical high energy storage efficiency and breakdown strength. In the present work, pore free Ca0.6Sr0.4TiO3 (CST) ceramics with various amounts of Mn dopants (0%, 0.1%, 0.2%, 0.3%, 0.4%, 0.5%, 1.0%, 1.5%, 2.0%) were prepared via solid state reaction method. P-E curves were measured under a temperature range of...
The building, being one of the largest energy consumers, accounts for over 40% of the global energy consumption. The traditional Heating, Ventilation and Air Conditioning (HVAC) and lighting systems cause considerable energy wastes in the building since they cannot adapt to the time-varying occupancy levels, which is expensive to measure with dedicated sensing systems. We propose an indirect method...
Localized spectral loss can be severely detrimental to Kerr frequency comb generation. We examine its impact in details and propose an effective way for robust comb generation with a spectral loss of even 300 dB/cm.
In-fiber optical devices have low insertion loss, high reliability and compatibility with the fiber systems and transmission network. They are different from the in-line components that are typically produced by coupling the light in and out of the optical fiber to and from some bulk or integrated optical waveguide device, therefore, inducing high insertion loss. An in-fiber optical polarizer is a...
We present a dispersion-engineered Ge-on-Si waveguide with flat and low dispersion from 3 to 11 μm, which enables coherent supercontinuum generation from 3700 to 9240 nm using a sub-picosecond pulsed pump.
A SOI pedestal waveguide can greatly reduce the material absorption induced loss at the Mid-IR wavelengths range. We propose using the second-order TE mode to reduce the propagation loss of the waveguide by >7 times compared to the fundamental TE mode.
Cylindrical vector beams (CVBs) have been widely used in many applications, such as optical tweezers, surface plasmon resonance and material processing, because of its symmetric intensity and polarization. Few-mode fiber grating (FMFG) as the high order mode selector has the advantages of high-efficiency, low cost and all-fiber structure. We demonstrate cylindrical vector pulse generation from a mode-locked...
This paper is concerned with finding the k shortest routes or paths in a network where each node has some specific time windows only within which is the node accessible. Because of such time windows at nodes, classical methods for the k shortest paths problem (k-SPP) is not applicable to the k shortest paths problem in a time-window network (k-SPPTW). Taking inspiration from the natural ripple-spreading...
The decentralized caching is studied in hierarchical networks, where users request contents through intermediate nodes (helpers) from a file server. By placing contents randomly and independently in each node and carefully designing the data delivery, the correlations of the pre-stored contents across layers can be utilized to reduce the transmission rate in each layer. A hybrid caching scheme is...
With the increase of dimensions and complexity of current engineering problems, parallel evolutionary algorithm which take advantage of population division and information exchange among processors has been introduced for years. However, low solution ability of each sub-group and high communication load between them are always seen as the biggest bottlenecks which hinder parallel evolutionary algorithm...
This paper presents an automatic interpretation method for pointer-type meter reading from complex environment based on visual saliency. Compared with the manually based methods, the proposed approach is based on image processing and automatic technique, avoiding the problems of low efficiency, high subjective, as well as inaccurate precision that are caused by manual judgement. Firstly, a localized...
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