Abstract:

Abstract:

Abstract:A high-bandwidth, high-sensitivity fully differential optoelectronic integrated receiver is implemented in a chartered 3.3 Vstandard 0.35 um analog CMOS process. To convert the incident light into a pair of fully differential photo-currents, anovel fully differential photodetector is proposed, which is composed of two completely identical photodiodes. The mea-surement results show that the receiver achieves a 1.11 GHz 3 dB bandwidth and a -13 dBm sensitivity for a 10-12 bit error at1.5 Gb/s data rate under illumination by 850 nm incident lights.

Abstract:The CIGS thin films are prepared by co-evaporation of elemental In, Ga and Se on the substrates of Mo-coated glasses at400℃ followed by co-evaporation of elemental Cu and Se at 550℃. We study the structural and electrical properties usingXRD, XRF and Hall effect measurements. In general, Cu(In,Cra)5Se8 phase exists when Cu/(In Ga) ratio is from 0.17 to0.27, Cu(In,Ga)3Se5 phase exists for Cu/(In Ga) ratio between 0.27 and 0.41, Cu2(In,Ga)4Se7 and Cu(In,Ga)2Se3.5 phasesexist for Cu/(In Ga) ratio between 0.41 and 0.61, and OVC(or ODC) and CuIn0.7Ga0.3 Se2 phases exist when Cu/(In Ga)ratio is from 0.61 to 0.88. With the increase of Cu/(In Ga) ratio, the carrier concentrations of the films gradually increase,but the electrical resistivity gradually decreases.

Abstract:The memory devices in multi-valued logic are of most significance in modern research. This paper deals with the imple-mentation of basic memory devices in multi-valued logic using Savart plate and spatial light modulator (SLM) basedoptoelectronic circuits. Photons are used here as the carrier to speed up the operations. Optical tree architecture (OTA) hasbeen also utilized in the optical interconnection network. We have exploited the advantages of Savart plates, SLMs andOTA and proposed the SLM based high speed JK, D-type and T-type flip-flops in a trinary system.

Abstract:Differential evolution algorithm is used to solve the inverse problem of strain distribution in tibet Bragg grating (FBG).Linear and nonlinear strain profiles are reconstructed based on the reflection spectra. An approximate solution could beobtained within only 50 rounds of evolutions. Numerical examples show good agreements between target strain profilesand reconstructed ones. Online performance analysis illuminates the efficiency and practicality of differential evolutionalgorithm in solving the inverse problem of FBG.

Abstract:A multi-channel free space optical interconnection component, fiber optic rotary joint, was designed using a Dove prism.When the Dove prism is rotated an angle of α around the longitudinal axis, the image rotates an angle of 2α. The opticalinterconnection component consists of the signal transmission system, Dove prim and driving mechanism. The planetarygears are used to achieve the speed ratio of 2:1 between the total optical interconnection component and the Dove prism.The C-lenses are employed to couple different optical signals in the signal transmission system. The coupling loss betweenthe receiving fiber of stationary part and the transmitting fiber of rotary part is measured.

Abstract:A YVO4 crystal Gland-Foucasult prism is manufactured. The relationships between prism structure angle and view fieldangle are studied with different wavelengths. The results show that the prism with the structure angle of 28.18° has a goodextinction ratio and the transmission characteristic in both visible and near-infrared regions.

Abstract:A passively Q-switched mode-locked Nd:GdYVO4 laser is successfully demonstrated by using a piece of GaAs crystalgrown at low temperature as the passively saturated absorber and the output coupler. Fundamental properties of the Nd:GdYVO4 laser are investigated. The maximum average output power of 3.5 W is obtained by using plainsphere when theincident pumping power is 10 W, which corresponds to an optical-optical coversion efficiency of 35%. The thresholdpower for the Q-switching mode-locked is 1.2 W. The maximum average output power of 1.72 W is obtained by usingGaAs when the incident pumping power is 10 W, mode-locked pulse train with a repetition rate of -113 MHz is achieved.At the incident laser pumping power of 7 W, the modulation depth is 100%.

Abstract:A high-bandwidth, high-sensitivity fully differential optoelectronic integrated receiver is implemented in a chartered 3.3 V standard 0.35 μm analog CMOS process. To convert the incident light into a pair of fully differential photo-currents, a novel fully differential photodetector is proposed, which is composed of two completely identical photodiodes. The measurement results show that the receiver achieves a 1.11 GHz 3 dB bandwidth and a ?13 dBm sensitivity for a 10^?12 bit error at 1.5 Gb/s data rate under illumination by 850 nm incident lights.

Abstract:The staggered InGaN quantum well (QW) structure and the conventional InCraN QW structure for the emission at a particu-lar wavelength of 400 nm are designed and theoretically investigated, including the distribution of the carriers' concentration,the radiative recombination rate, the Shockley-Read-Hall (SRH) recombination rate as well as the output performance andthe internal quantum efficiency. The theoretical result indicates that the staggered QW structure offers significant improve-ment of carriers' concentration in the QW, especially the hole concentration. The output power and the internal quantumefficiency also show 32.6 % and 32.5 % enhancement, respectively, in comparison with that of the conventional InGaNQW structure. The reduction of the electron overflow can be the main factor for the improvement of the optical perfor-mance for novel staggered InGaN QW structure.

Abstract:Differential evolution algorithm is used to solve the inverse problem of strain distribution in fiber Bragg grating (FBG). Linear and nonlinear strain profiles are reconstructed based on the reflection spectra. An approximate solution could be obtained within only 50 rounds of evolutions. Numerical examples show good agreements between target strain profiles and reconstructed ones. Online performance analysis illuminates the efficiency and practicality of differential evolution algorithm in solving the inverse problem of FBG. This work has been supported by Major Program of National Natural Science Foundation of China (No. 60537050)

Abstract:A multi-channel free space optical interconnection component, fiber optic rotary joint, was designed using a Dove prism. When the Dove prism is rotated an angle of α around the longitudinal axis, the image rotates an angle of 2α. The optical interconnection component consists of the signal transmission system, Dove prim and driving mechanism. The planetary gears are used to achieve the speed ratio of 2:1 between the total optical interconnection component and the Dove prism. The C-lenses are employed to couple different optical signals in the signal transmission system. The coupling loss between the receiving fiber of stationary part and the transmitting fiber of rotary part is measured. This work has been supported by the National Natural Science Foundation of China (No. 60577013), program for New Century Talents in University, Ministry of Education of China.

Abstract:A model of universal single layer organic solar cells in metal-insulator-metal (MIM) representation involving field-depen-dent carrier mobility is set up. The current-voltage characteristics as well as the distribution of electron density, hole density and recombination rate on a set of parameters are simulated. Subsequently, the dependences of the short-circuit current density (Jsc) and open-circuit voltage (Voc) on the electron and hole zero-field mobility, excitation generation rate, energy gap, as well as electron-hole pair distance in an excitation are investigated. It is demonstrated that the enhancement of either the electron mobility or the hole mobility can contribute to the increase of Jsc in the devices. The increase of the hole mobility can lead to the improvement of both Jsc and Voc, and the simultaneous increase of the electron mobility and hole mobility will greatly elevate Jsc but maintain a steady Voc. Additionally, all the increases of the excitation generation rate, energy gap and electron-hole pair distance are beneficial to both the remarkable increases of Jsc and Voc of the devices.

Abstract:Through analyzing theoretically the temperature effect of the optical-fiber Raman backscattering, a distributed temperaturesensor is designed based on the single-mode fiber. Demodulation methods of temperature transduction are compared, andthen the demodulation method using the ratio of the anti-Stokes and the Stokes Raman backscattering intensity is adopted.Both the hardware composition and the software realization of the system are introduced in detail.The experiment showsthat the distinguishing ability of the temperature and that of the space are 1℃ and 2 m, respectively, and that the systemresponse time is about 180 s with a sensing range of 5 km and with a temperature measurement range of 0-100℃.

Abstract:To obtain the coupling characteristics between slab wave-guides including lift-handed material, we modify the coupledwave equations by using Maxwell's equations. First, we obtain new-couplid wave equations and new-coupling coefficient.Second, the coupling between two identical five-layer slab wave-guides where their cores are left-haaded material, but theircladdings are right-handed materials is studied. The coupling coefficient for even TE mode which is more complex than thatof the riglt-handed material slab wave guides, is obtained.

Abstract:A passively Q-switched mode-locked Nd:GdYVO₄ laser is successfully demonstrated by using a piece of GaAs crystal grown at low temperature as the passively saturated absorber and the output coupler. Fundamental properties of the Nd: GdYVO₄ laser are investigated. The maximum average output power of 3.5 W is obtained by using plainsphere when the incident pumping power is 10 W, which corresponds to an optical-optical coversion efficiency of 35%. The threshold power for the Q-switching mode-locked is 1.2 W. The maximum average output power of 1.72 W is obtained by using GaAs when the incident pumping power is 10 W, mode-locked pulse train with a repetition rate of ∼113 MHz is achieved. At the incident laser pumping power of 7 W, the modulation depth is 100%.

Abstract:A YVO₄ crystal Gland-Foucasult prism is manufactured. The relationships between prism structure angle and view field angle are studied with different wavelengths. The results show that the prism with the structure angle of 28.18° has a good extinction ratio and the transmission characteristic in both visible and near-infrared regions.

Abstract:SiC granule films were fabricated onto porous glass substrate by RF-magnctron sputtering. Photoluminescence(PL) mea-surements show that there are light emissions at three different wavelengths. Ultraviolet emission peaked at 360 nm origi-nated from the band-band transmission of SiC nanoparticles with relatively small size. The 370 nm light emission was dueto the luminescence of the nano-skeletons of porous glass that was formed during the etching of the glass substrate. Theblue emission at about 460 nm was associated with the recombination of the excited electron and O-deficient defectsappeared at the interface between SiC nanoparticles and the porous glass. Furthermore, the optimal PL performance wasobtained when SiC deposited time was 1 h and the glass substrate was etched for 20 min in the annealing sample (450℃).

Abstract:Nitrogen-doped diamond films have been synthesized by EA-CVD (electron assisted chemical vapor deposition) technique.The quality and nitrogen impurity states of the diamond films are characterized by SEM, raman spectroscopy, XPS and EPRspectroscopy, respectively. The results show that the morphology changes from well-defined facets to cauliflower-like structures,the content of amorphous carbon increases and the quality drops with increasing the nitrogen flow rate. Furthermore, in thefilms, it can be observed that nitrogen impurity exists in the forms of Ns0, [N-V]0 and [N-V]-1. The contents of [N-V]0 and[N-V]-1 are lower when the nitrogen flow rate is relatively high, and the concentration of Ns0 varies from 15 ppm to 483 ppm.

Abstract:Using transfer matrix method, the optical transmission properties of 1-D photonic crystals composed partially of negativerefraction media are analyzed. The transmission spectra of periodic photonic crystal, chirped photonic crystal and apodizedphotonic crystal are numerically simulated respectively. By contrast with optical transmission properties of ordinary photo-nic crystals made of positive refraction media, the transmission spectra of apodized photonic crystal become unregular, theBragg flat-headed area recurs but the peak of transmission does not change significantly. Futhermore, the band gap rangeof chirped photonic crystal diminishes gradually.

Abstract:The memory devices in multi-valued logic are of most significance in modern research. This paper deals with the implementation of basic memory devices in multi-valued logic using Savart plate and spatial light modulator (SLM) based optoelectronic circuits. Photons are used here as the carrier to speed up the operations. Optical tree architecture (OTA) has been also utilized in the optical interconnection network. We have exploited the advantages of Savart plates, SLMs and OTA and proposed the SLM based high speed JK, D-type and T-type flip-flops in a trinary system.

Abstract:We propose a new integrated method which covers addition of any two signed digit numbers in all-optical domain. Toimplement this scheme we have exploited some photo-refractive characters of optical non-linear materials, which mayexperience 0.1-0.2 dB attenuation loss as silica is used as non-linear medium. Moreover, the attenuation loss may bereduced to 0.001 dB/m if we consider the use of slow light at 1.56 um.

Abstract:BP neural network is introduced to the fault location field of DWDM optical network in this paper. The alarm characteris-tics of the optical network equipments are discussed, and alarm vector and fault vector diagrams are generated by analyzingsome typical instances. A 17×14×18 BP neural network structure is constructed and trained by using MATLAB. Bycomparing the training performances, the best training algorithm of fault location among the three training algorithms ischosen. Numerical simulation results indicate that the sum squared error (SSE) of fault location is less than 0.01, and theprocessing time is less than 100 ms. This method not only well deals with the missing alarms or false alarms, but alsoimproves the fault location accuracy and real-time ability.

Abstract:Mechanical vibration of target structures will modulate the phase function of radar backscattering, and will induce thefrequency modulation of returned signals from the target. It generates a side bands of the target body Doppler frequencyshift, which is helpful for target recognition. Based on this.a micro-Doppler atomic storehouse is built for the targetrecognition, and four kinds of common classifiers are used separately to perform the classified recognition. The simulationexperimental results show that this method has high recognition rate above 90%.

Abstract:The rapidness and stability of background extraction from image sequences are incompatible, that is, when a conventionalCraussian mixture models (GMM)is used to rebuild the background, if the background regions of the scene are changed, theextracted background becomes bad until the transition is over. A novel adaptive method is presented to adjust the learningrate of GMM in a Hilbert space. The background extraction is treated as a process of approaching to a certain point in theHilbert space, so the real-time learning rate can be obtained by calculating the distance between the two adjacent extractedbackground images, and a judgment method of the stability of background is got too. Compared with conventional GMM,the method has both high rapidness and good stability at the same time, and it can adjust the learning rate online. Theexperiment shows that it is better than conventional GMM, especially in the transition process of background extraction.

Abstract:Numerical simulation has been performed on the optical transmission enhancement properties of a one-dimensional Agfilm single slit structure with grooves. The results show that the position, depth and number of the grooves have greatinfluence on the optical transmission, and surface plasmon polariton and resonance mode are the primary factors. Themaximal extinction ratio of 35.8 dB is achieved in the single slit structure by adjusting groove depth.

Abstract:In the context of cavity quantum electrodynamics (QED), a potential scheme is proposed to generate entangled coherentstates. The scheme includes twice interactions of two-level atoms with cavities. In the first interaction, two atoms are sentinto a microwave cavity with the large detuning respectively. And then the second interaction is that the two atoms enteranother microwave cavity and are driven by a resonant classical field meantime. When we choose the proper interactiontime and make measurement on the two atoms, the two microwave cavity mode fields are determinatively entangled. Inaddition, it is easy to generalize the scheme to multi-cavity and multi-atom.