基于光波检测的智能ODN故障管理系统

智能光分配网络(ODN)系统在线路端口引入电子标签一定程度上提高了路由信息收集及工单收发的效率,光纤网络的管理更加自动化,但光纤网络的无源特性使这种改动在业务正在运营的已建机房实施困难。提出通过利用检测光波可携带线路信息的特性,实现智能化路由更新、故障检测,并结合人工智能技术,设计出更加完善的故障管理系统,以解决因光网络无源特性造成的智能ODN系统兼容性问题。

Fast Digital Correlation Calculation Method in Extended Beacon Wavefront Detection

On the basis of Hartmann Shack sensor imaging analysis, a new method is presented with which the wavefront slope can be obtained when the object is incoherent and extended. This method, which is demonstrated by both theoretical interpreting and computer simulation, explains how to measure the wavefront slope difference between two sub apertures through the determination of image displacements on detector plane. It includes a fast and accurate digital algorithm for detecting wavefront disturbance, which is much suitable for realization in such electrical hardwares as digital signal processors.

Automated visual position detection and adjustment for optical waveguide chips and optical fiber arrays

The alignment coupling between optical waveguide chips and optical fiber arrays is the basis of the alignment coupling of planar optical waveguide devices, and the precise position detection with angle and spacing adjustments is one of the key steps of alignment coupling. A methodology for position detection, and angle and spacing adjustment was proposed for optical waveguide chips and optical fiber arrays based on machine vision. The experimental results show angle detection precision levels higher than 0.05°, line detection precision levels higher than 0.1 μm, and detection time less than 2 s. Therefore, the system developed herein meets the precise requirements necessary for position detection, and angle and spacing adjustments for optical waveguide chips and optical fiber arrays.

Calculation of Ge_(0.5)Si_(0.5)—Si Superlattice Photodetectors on Ge_(0.05)Si_(0.95) Waveguides:The Optimum Parameters

Abstract: The optimum parameters are calculated by the large cross - section theory and mode cut - off equation. The effect on reverse bias voltage is analysed by the doping concentration in n+ - Si. This is significant because the reverse bias increases sharply when the doped concentration in n+ - Si is less than 1 x 10~20 cm-3.

The intensity calculation of the gas absorption line by multi-line Voigt fitting

Adopted the distribution feedback type （DFB） laser to measure the coal mine gas methane, according to the methane located 1.6 μm nearby 2v3 with a R9 direct absorption spectrum, attraction wire intensity of each line was calculated through the multi-line Voigt fitting. The experimental result indicates that in the obtained four attraction recover of wire, the maximum deviation is 2.7%, and the minimum deviation is 0.02%, other results are all in experimental error scope. This research method may apply in the spectrum survey methane gas density, it has characteristics including high precision, strong selectivity, fast response and so on.

An all optical fiber gas sensor of NH3 and CO based on based on the spectral absorption and harmonic detection

An all optical fiber gas sensor is presented to detect the concentration of NH3 and CO. Based on the spectral absorption, The wideband light source is used to reflect two narrowband spectra by fiber grating of different duty. and piezoelectric ceramics to obtain narrowband output light. The high sensitivity detection can be measured from the second harmonic signal. The two narrowband spectra are corresponding to the absorption spectra of NH3 and CO. Concentration detection are realized by the detection of variety of light intensity. Sensitivity is proved and cost is reduced.

Experimental research on benzene detection using ion mobility spectrometer with a laser ionization source

An ion mobility spectrometer equipped with a laser ionization source is used for the sensitive detection of benzene.Mobility spectra of the benzene are presented.We also discussed the mobility spectra at various concentrations and drift voltages.Detection limits are determined to be in the upper ppb_v range.In the end,the advantages and possibilities of this technique are briefly discussed.

Computational Study of the A0 Scattered Field Due to an Edge Delamination

Delamination detection presents a pertinent problem for SHM be no visible signs of the damage on the surface of the structure. （structural health monitoring）, as in most cases, there may This study investigates the scattering of a zeroth-order anti-symmetric （A0） Lamb wave mode by an edge delamination using the commercial FE （finite element） package ABAQUS. The Ao Lamb mode is chosen because the corresponding stress distribution is more sensitive to delamination than is the case for symmetric modes. The paper presents results for the scatter field for various angles of incidence, and for varying defect sizes. The regime of small defect size relative to the incident wavelength is of particular interest for SHM as it corresponds to early damage detection. It is shown that, in this regime the scattered field appears to originate from a point source at the origin of the delamination, and the corresponding amplitude is linearly proportional to area of the delamination. These results can be used to guide the use of Lamb waves to detect and quantify edge delamination in plate-like structures.

Organic single-crystal phototransistor with unique wavelength-detection characteristics

Organic phototransistors based on high-quality 2,8-dichloro-5,11-dihexyl-indolo[3,2-b]carbazo(CHICZ)single crystals show the highest photoresponsivity of 3×10^3 A W^-1, photosensitivity of 2×10^4 and the detectivity can achieve 8.4×10^14 Jones. We also discovered good linear dependence of log(photosensitivity) versus the wavelength when the devices were illuminated with a series of sameintensity but different-wavelength lights. The organic phototransistors based on CHICZ single crystal have potential applications in wavelength-detection.

FBG-based ultrasonic wave detection and acoustic emission linear location system

The ultrasonic (US) wave detection and an acoustic emission (AE) linear location system are proposed, which employ fiber Bragg gratings (FBGs) as US wave sensors. In the theoretical analysis, the FBG sensor response to longitudinal US wave is investigated. The result indicates that the FBG wavelength can be modulated as static case when the grating length is much shorter than US wavelength. The experimental results of standard sinusoidal and spindle wave test agree well with the generated signal. Further research using two FBGs for realizing linear location is also achieved. The maximum linear location error is obtained as less than 5 mm. FBG-based US wave sensor and AE linear location provide useful tools for specific requirements.

Response Analysis of Ultrasonic Sensing System Based on Fiber Bragg Gratings of Different Lengths

In recent years, fiber Bragg gratings （FBGs） have been widely used in ultrasonic detection for practical structural health monitoring in light of its unique advantages over the conventional sensors. Although FBGs have been successfully tested in ultrasonic inspection, the effect of the grating length on the sensitivity of the FBG ultrasonic sensing system is yet to be analyzed. Hence, using the simulation model, the main influencing factor on the sensitivity of the ultrasonic sensing system with different lengths gratings was first investigated. In the following experiment, the ultrasonic responses of the sensing system with six different lengths FBGs were obtained, respectively. The theoretical analysis and the experimental results would be useful for sensitivity improvement of the FBG-based ultrasonic and acoustic emission sensing system.

Hydrogen-bond organized 2D metal–organic microsheets:direct ultralong phosphorescence and color-tunable optical waveguides

Ultralong phosphorescent materials have numerous applications across biological imaging, lightemitting devices, X-ray detection and anti-counterfeiting. Triplet-state molecular phosphorescence typically accompanies the singlet-state fluorescence during photoluminescence, and it is still difficult to achieve direct triplet photoemission as ultralong room temperature phosphorescence(RTP). Here, we have designed Zn-IMDC(IMDC, 4,5-imidazoledicarboxylic acid) and Cd-IMDC, two-dimensional(2D)hydrogen-bond organized metal–organic crystalline microsheets that exhibit rarely direct ultralong RTP upon UV excitation, benefiting from the appropriate heavy-atom effect and multiple triplet energy levels. The excitation-dependent and thermally stimulated ultralong phosphorescence endow the metal–organic systems great opportunities for information safety application and temperature-gated afterglow emission. The well-defined 2D microsheets present color-tunable and anisotropic optical waveguides under different excitation and temperature conditions, providing an effective way to obtain intelligent RTP-based photonic systems at the micro-and nano-scales.

Organic photodetectors based on transparent electrodes for application in ultraviolet light detection

A high performance heterojunction organic ultraviolet photodetector based on NPB and Bphen has been fabricated. A trans- parent conducting polymer PEDOT：PSS coated quartz substrate instead of ITO coated glass substrate as anode is propitious to detect shorter wavelength ultraviolet light. As a result, the device shows a low dark current density, a high responsivity of 502 mA/W and a detectivity of 2.67x1012 cm Hz1/Zfw which is illuminated by a 220 nm ultraviolet light with an intensity of 1.6 mW/cm2. Moreover, the performance of the PEDOT：PSS transparent electrode device is better than the semi-transparent A1 electrode device electrode because of the higher transmittance and electrode properties.

A near-infrared methane detection system using a 1.654 μm wavelength-modulated diode laser

By adopting a distributed feedback laser(DFBL) centered at 1.654 μm, a near-infrared(NIR) methane(CH4) detection system based on tunable diode laser absorption spectroscopy(TDLAS) is experimentally demonstrated. A laser temperature control as well as wavelength modulation module is developed to control the laser's operation temperature. The laser's temperature fluctuation can be limited within the range of-0.02—0.02 °C, and the laser's emitting wavelength varies linearly with the temperature and injection current. An open reflective gas sensing probe is realized to double the absorption optical path length from 0.2 m to 0.4 m. Within the detection range of 0—0.01, gas detection experiments were conducted to derive the relation between harmonic amplitude and gas concentration. Based on the Allan deviation at an integral time of 1 s, the limit of detection(Lo D) is decided to be 2.952×10^(-5) with a path length of 0.4 m, indicating a minimum detectable column density of ~1.2×10^(-5) m. Compared with our previously reported NIR CH_4 detection system, this system exhibits some improvement in both optical and electrical structures, including the analogue temperature controller with less software consumption, simple and reliable open reflective sensing probe.

Low-voltage-modulated perovskite/organic dual-band photodetectors for visible and near-infrared imaging

Visible and near-infrared(NIR)light dual-band photodetectors(PDs)have potential applications in signal detection,bioimaging,optical communications and safety monitoring.Herein,we report an ultrafast perovskite/organic heterojunction dual-mode PD with a voltage-modulated photoresponse range in visible and NIR spectra.The PD,comprising a perovskite layer to absorb visible light(500–810 nm)and an organic bulk heterojunction layer for NIR light absorption(810–950 nm),exhibited a switchable spectral response in the visible or NIR bands.The voltage-modulated visible and NIR photoresponses of the PD were attributable to controlled charge photogeneration in perovskite and organic blend thin films under different bias polarities.The device exhibited peak responsivities of 93.5 and 102.2 mA/W in the visible and NIR bands,respectively;a high detectivity of 4.3×10^(9) Jones(at forward bias of 0.7 V and incident 625 nm light)and 1.6×10^(12) Jones(at reverse bias of–1.5 V and incident 900 nm light);a fast microsecond response time;and a wide dynamic range(>120 dB)both in the visible mode and NIR mode.Also,this voltage-modulated dual-band PD shows promising applications in visible light and NIR imaging,which is proven by demonstrating a PD array with 25 pixels(5×5).

Water Vapor Detection System Based on Scanning Spectra

Scanning the absorption spectral line of water vapor through wavelength around 1368.597nm is successfully used to measure the value of micro-moisture content. The synchronous superposition average of original signal algorithm based on labview is innovated and applied to detecting weak spectrum absorption signal instead of low pass filter. Two data processing methods are used to get the concentration of water vapor in ppm： one is a general formula method which has newly deduced a general formula to calculate the concentration of gas with temperature and beam intensity ratio when the pressure is equal to or greater than 1 atm; the other is engineering calibration method which is proved to have high resolution and accuracy with the fitted curve of beam intensity ratio and concentration in ppm when the temperature changes form 258K to 305K and the pressure ranges from 1 atm to 5 atm.