Abstract:We discuss the technical rationale, challenges, and potential for achieving “optics-to-the chip” via the intimate integration of photonics components such as lasers, detectors, and modulators with VLSI electronics. We review the progress made towards commercializing this technology for high-density optical transceivers and switching products.

Abstract:CdSe nanocrystals were prepared by a colloidal chemical approach using CdO and Se powder as precursors in an organic system of TOPO/TOP, and a multilayered electroluminescence device was fabricated with CdSe as emitting layer. The results show that the photoluminescence spectra of the CdSe nanocrystals almost cover the whole visible region and the full width at half maximum (FWHM) is appropriately 200 nm. The electroluminescence spectrum of the multilayered device at different voltages was investigated. The electroluminescence intensity is enhanced with increasing operating voltage, and the CIE coordinates of the device change from (0.34, 0.37) at 6 V to (0.44, 0.46) at 20 V as the operating voltage increases, which indicates that the colors of the device could be tuned by the operating voltage. Supported by the National Natural Science Foundation of China (No. 90301004, No. 10434030 and No. 60406005); the “973” National Key Basic Research Special Foundation of China (No. 2003CB314707); the New Star Program for Science and Technology of Beijing City (No. 2004B10).

Abstract:In this paper, the experiment on an all-optical switching is reported based on a microstructure fiber(MF)-nonlinear optical loop mirror (NOLM). In the experiment, a 25-meter-long MF (γ=36W⁻¹km⁻¹@1550 nm) is used as a nonlinear medium of the nonlinear optical loop mirror and the input signal is generated by a 10 GHz tunable picosecond laser source, with a full-width at half-maximum (FWHM) of 2 ps and centered at 1550 nm. With the increase of input power, a π nonlinear phase shift is obtained by a 40/60 coupler in the experiment, but the same result can not be found by a 48/52 coupler. Additionally, the switching devices can also be used as an all-optical regeneration. This work is supported by the National Basic Research Program of China(2003CB314900), the Key grant Project of Chinese Ministry of Education (NO. 104046) and the National 863 High Technology Project of China (2003AA311010)

Abstract:The mathematic model of the line structured-light 3-D vision sensor was established. A separating-parameter method was proposed to calibrate the structure parameter, and a calibration target was designed. In the calibrating process, complicated measurement is avoided and the calibration is fast and easy to carry out, which simplifies the calibrating procedure. The experimental results show that the space measurement accuracy is better than 0.15 mm. This method is high efficient and practical in vision sensors calibration.

Abstract:A high power collimated diode laser stack is carried out based on fast-axis collimation and stack packaging techniques. The module includes ten typical continuous wave (cw) bars and the total output power can be up to 368W at 48. 6A. Using a cylindrical lens as the collimation elements, we can make the fast-axis divergence and the slow-axis divergence are 0.926 4° and 8.206° respectively. The light emitting area is limited in a square area of 18.3 mm×11 mm. The module has the advantage of high power density and offers a wide potential applications in pumping and material processing.

Abstract:Un-hydrogenated Diamond-like Carbon (DLC) films were prepared by pulsed laser deposition technique at different substrate temperature. The Raman spectra, the absorption and the photoluminescence spectra were measured. The dependence of structure and photoluminescence properties on deposition temperature were studied in detail. The experimental results indicate that the sp² sites form small clusters that consist of both olefinic chains and aromatic ring groups within the sp³ matrix. With raising deposition temperature, the optical band gaps increase from 1.87 to 2.85 eV. The main band of photoluminescence centered at around 700 nm shifts to short wavelength, and the intensity of this band increases. The photoluminescence can be attributed to carrier localization within an increasing sp² clusters. It was clarified that the DLC films are ordered with increasing deposition temperature.

Abstract:The absorption spectrum and photoluminescence spectrum of multiwalled carbon nanotubes (MWNTs) and the peaks related with Van Hove singularities (VHS) were obtained experimentally. Both the VHS formation and the change of band gaps in MWNTs depend on the intershell interaction. The VHS makes the probability of optical transitions enhanced, but the intershell interaction suppresses such radiative transitions. The excitation in the experiment involves a two-photon absorption process and the emission light has the effect of the optical frequency up-conversion.

Abstract:This paper presents an approach to calculate dispersion penalty for VSR-1 optical links. Based on parameters of a specific VSR-1 link, dispersion penalties are computed for various modal dispersion bandwidths respectively. The worst-case eye closure is expressed numerically by using the signal waveform at time 0, and the signal waveform is obtained in frequency domain through FFT algorithm. By this approach,the dispersion penalty is determined by the shape of transfer functions of the various components in the links. To simplify the derivation of multimode fiber link transfer function,a Gaussian form of normalized impulse response is used. This calculation approach can be used to estimate the worst-case dispersion penalty of VSR-1 links in the link budget analysis.

Abstract:In this paper,we numerically study chaotic synchronization communication system based on incoherent optical feedback and incoherent optical injection. The characteristics of the system, such as synchronization time,synchronization error, chaos shift keying encoding/decoding and modulation rate are analyzed. The results of simulation show that the system has good synchronization quality and good abilities of robust secure. The synchronization time is 1ns and the chaos shift keying encoding can reach a high rate of 1 Gbit/ s. The system has a good ability of robust secure. It proves the feasibility of the optical secure communication.

Abstract:Amplification effect of forward stimulated Brillouin scattering (SBS) lines on the forward pumped s-band discrete DCF fiber Raman amplifier (FRA) has been studied. Pump threshold power of the forward first order Stokes SBS (FSB1-), second order Stokes SBS (FSB2-) and third order SBS (FSB3-) in the forward pumped FRA are 1.5 mW, 1.4 mW and 1.7 mW, respectively. The Stokes SBS lines are amplified by FRA and fiber Brillouin amplifier (FBA) at the same time. Gain of amplification is given as G_A=G_R · G_B, where G_R is Raman gain and G_B is Brillouin gain. Saturation gain of FSB1-, FSB2- and FSB3- are about 52 dB, 65 dB and 65 dB, respectively. The saturation Raman gain of 10 km DCF forward FRA is about 14 dB, so Brillouin gain of FSB1-, FSB2- and FSB3- are about 38 dB, 51 dB and 51 dB, respectively. The forward cascaded SBS lines have been observed. Supported by the Great Scientific Research Project of Zhejiang Province, P. R. China under Grant No. 021101558

Abstract:Firstly, the JME (Jones matrix eigen) method is used to simulate the statistical characteristics of first- and second-order PMD in dispersion management system. Then, with help of the CNLSE (coupled nonlinear Schr?dinger equations), the effects of PMD on DMS (dispersion managed soliton) transmission is studied with a variatioal method. The simplified relationships of the statistical parameters of second-order and first-order of PMD in dispersion management system have been gotten, from which the detailed information of second-order can be obtained, if the condition of DGD is given. The results have shown that the first and second-order PMD (polarization mode dispersion) vectors influence the evolution of energy and Mean square of time displacement of DMS in high-speed bit rates systems. WhenD _PMD ^{1 st}>0.3 ps/km^1/2, we must consider some means of control (for example the filter) the restrain the PMD. [Continued from page 216]

Abstract:To study the performance of various error-control coding schemes, exact expressions and upper bounds on the pariwise codeword error probability (PEP) for several modulation schemes (OOK, SC-BPSK, BP-PM) used in atmospheric optical communication systems are derived. to simplify the computation, this research was under the assumption of weak turbulence. Moreover, by simulation of expressions, the performances of PEP in different modulation schemes are compared and the best one of them is given.

Abstract:According to the characteristics of high-order solitons, compressed picosecond pulses are numerically simulated in the photonic crystal fiber (PCF), by means of split-step Fourier method. The results show that, PCF enables input pulse with lower peak power to form high-order solitons for the purpose of femtosecond pulse-width compression. For example, 60- femtosecond pulse width was made for 1-ps initial pulse width only over the distance of 2.2 m. Besides, shorter optimum fiber length for compression and higher compression ratio could be obtained on the premise of pre-chirp technique.

Abstract:Quantum digital signature is the quantum scenario of classical digital signature. It makes use of quantum effects to provide unconditionally secure signature. We first present a prototype of quantum signature scheme using single photons and then discuss its extensions. The most important property of the proposed scheme is that it is not necessary for the scheme to use entangled states. The security of the scheme is based on quantum key distribution and quantum one-time pad proved as unconditionally secure. The present scheme is efficient in that it needs only single photons and von Neumann measurement. We also show a quantum circuit for the scheme.

Abstract:Log polar transformation is an important algorithm of space-variant vision theory. It well depicts the retinocortical mapping. Due to the logarithmic and the arctangent operation in the transformation,the log polar coordinate of an image is mostly a decimal fraction and the range is quite narrow. Aiming at solving these problems,this paper puts forward an inverse log polar transformation based on sub-pixel interpolation. The acquired log polar image of the new algorithm has no mosaic phenomenon,meanwhile it is a better simulation of retina-cortical mapping.

Abstract:This paper presents a robust color image hiding method based on YCbCr color system in discrete cosine transform (DCT) domain, which can hide a secret color image behind a public color cover image and is compatible with the international image compression standard of JPEG. To overcome the grave distortion problem in the restored secret image, this paper proposes a new embedding scheme consisting of reasonable partition of a pixel value and sign embedding. Moreover, based on human visual system (HVS) and fuzzy theory, this paper also presents a fuzzy classification method for DCT sub-blocks to realize the adaptive selection of embedding strength. The experimental results show that the maximum distortion error in pixel value for the extracted secret image is ± 1. And the color cover image can provide good quality after embedding large amount of data. This work is partially supported by National Science Foundation (Grant No. A0324676)

Abstract:The FDK algorithm is the most popular cone beam algorithm in the medical and industrial imaging field. Due to data insufficiency acquired from a circular trajectory, the images reconstructed by the FDK algorithm suffer from the intensity droping with increasing cone angle. To overcome the drawback, a modified FDK algorithm is presented by convert the 1D ramp filtering direction from along the horizontal lines to along the nutating lines based on the result of Turbell. Unlike Turbell's method, there is no need for our algorithm to rebin the cone-beam data into 3D parallel-beam data before reconstructing. Moreover pre-weighting of the projection data is corrected by compensating for the cone angle effect. In addition, another correction term derived from the result of Hu is also induced into our algorithm. The simulation experiments demonstrate that the final algorithm can suppress the intensity drop associated with the FDK algorithm. This work was sponsored by Youth Foundation Project of Liaoning Province Education Department. (NO. 2004F057)

Abstract:Influenced by detectors' material, manufacturing technology etc, every detector in infrared focal plane array (IRFPA) will output different voltages even if their input radiation flux is the same. And this is called non-uniformity of IRFPA. At the same time, the high background temperature, low temperature difference between targets and background and the low responsivity of IRFPA result in low contrast of infrared images. So non-uniformity correction and image enhancement are important techniques for IRFPA imaging system. This paper proposes a new real-time infrared image processing system based on Field Programmable Gate Array(FPGA). The system implements non-uniformity correction, image enhancement and video synthesization etc. By using parallel architecture and pipeline technique, the system processing speed is as high as 50Mx12bits per second. It is appropriate greatly to a large IRFPA and a high frame frequency IRFPA imaging system. The system is miniatured in one FPGA.

Abstract:We present a new multi-scale geometrical analysis method for ophthalmic image contrast enhancement based on the contourlet transform. The contourlet transform has better performance in representing edges than wavelets due to its anisotropy and directionality, and is therefore well-suited for multiscale edge enhancement. We modify the contourlet coefficients in corresponding subband and take the noise into account for more precise reconstruction and better visualization. We compare this approach with enhancement based on the curvelet transform, and the traditional Histogram Stretching (HS). Our findings are that contourlet based enhancement out-performs other enhancement methods on low contrast and dynamic range images, and can clearly identify the vessels and nerves in an ophthalmic image.

Abstract:The statics characteristics of two coupled Bose-Einstein condensate (BEC) dark solitons trapped in an optical lattice are investigated with the variational approach. It is found that the interaction between a ‘kink’ and an ‘anti-kink’ with opposite phase gradients is effectively repulsive, and the optical lattice can be controllably used to produce a pair of static BEC dark solitons. Its effect depends on the initial location of the BEC dark solitons, the lattice amplitude and wave number. Supported by the Science and Technology Program of Education Department of Hubei Province under Grant No. B20052202, and the Fund of Natural Science of Hubei Province under Grant No. 2004ABA112.

Abstract:An all-optical diode behavior that uses a nonlinear one-dimensional photonic crystal (NPC) with a defect Kerr medium is numerically simulated by the use of a nonlinear finite-difference time-domain (NFDTD) method. The numerical results show that for an incident pulse with appropriate intensity and temporal width, the transmittance can be several times greater in one direction of NPC than in the opposite direction at the pulse carrier frequency. This behaves like an all-optical diode and has promising applications in some areas such as optical isolation and all-optical processing. The ways to obtain low threshold of pulse field strength to realize an all-optical diode are also analyzed in detail. Supported by the National Natural Science Foundation of China (90201027,10374120)

Abstract:The characteristics of ALA absorption spectra under different conditions are studied with spectrometers. The results indicate that the wavelength of ALA,corresponding to the strongest absorption peak, is 282 nm under different conditions. The content of PplX synthesized is in direct proportion to the density of Jurkat cells. The most suitable culture time is 8 hours in order to synthesize more PplX. FCS has a block effect on the synthesis of PpIX.

Abstract:Optoelectronics Letters is the companion journal to Journal of Optoelectronics Laser (the core journal in Chinese) . The purpose of Optoelectronics Letters is reporting the new important results in the fields of optoelectronics /photonics in English to a…