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Kashi, China

Du Y.,Central China Normal University | Du Y.,Xinjiang Normal University | Zhang G.,Central China Normal University | Wu Y.,Central China Normal University | And 6 more authors.
Optical Engineering | Year: 2013

Ultrafast-photonic logic circuits are crucial elements to perform ultrafast-optical signal processing functions in the next-generation ultrahigh- speed networks. A 160 Gbit/s all-optical data distributor based on cross-phase modulation in a single highly nonlinear fiber is investigated and demonstrated. The numerical calculation is conducted, and the result shows that the data distributor can be realized in 160 Gbit/s for the data signals of return-to-zero format with logical correctness and high quality. To evaluate the performance of the scheme, the Q-factor of the output signal on signal wavelength, the peak power of signals, the initial delay, and the filter position are calculated and discussed, respectively. The proposed data distributor is suitable for ultrafast applications for the emerging all-optical networks. © 2013 Society of Photo-Optical Instrumentation Engineers.

Yi X.,Kashi Normal College
Wei sheng wu xue bao = Acta microbiologica Sinica | Year: 2011

To study the degradation of pyridine and quinoline by two Pseudomonas. Based on the analysis of 16S rRNA gene sequence homology and the intergenic spacer region sequence, the two isolates were identified. The degradation capability of pyridine and quinoline was determined according to spectrophotometry and Electrospray Ionisation/Mass Spectrometry (ESI/MS). The degrading plasmids were detected by plasmid curing and the possible degrading genes were also cloned. The two isolates were identified as Pseudomonas and nominated XJUHX-1 and XJUHX-12. The two Pseudomonas were tolerant with pyridine and quinoline and two and four possible metabolites were detected in the culture medium containing quinoline and pyridine, respectively. The degrading capability of curing plasmids was lower than the crude isolates. The gene segments coding for the NADH (acceptor) reductase component OxoR for quinoline degradation and nitrogenase reductase (NifH) of denitrification for pyridine degradation were amplified from the genome of XJUHX-1 and XJUHX-12, both were cloned and expressed in E. coli BL 21 producing recombinant proteins with molecular mass of 43 kDa and 16 kDa. The two isolates could degrade pyridine and quinoline respectively.

Wu Y.,Central China Normal University | Wu Y.,Kashi Normal College | Zhang G.,Central China Normal University | Guo L.,Kashi Normal College | And 2 more authors.
Journal of Applied Physics | Year: 2014

Based on Auger scattering mechanism, carrier-carrier scattering dynamics between the two-dimensional carrier reservoir (also called wetting layer, i.e., WL) and the confined quantum dot ground and first excited state in quantum-dot semiconductor optical amplifiers (QD-SOAs) are investigated theoretically in this paper. The scattering rates for independent electron and hole densities are calculated. The results show an ultra-fast carrier capture (relaxation) rate up to 1 ps-1, and there is a complex dependence of the Coulomb scattering rates on the WL electron and hole densities. In addition, due to the different effective mass and the level distribution, the scattering rates for electron and hole are very different. Finally, in order to provide a direction to control (increase or decrease) the input current in realistic QD-SOA systems, a simple method is proposed to determine the trends of the carrier recovery rates with the WL carrier densities in the vicinity of the steady-state. © 2014 AIP Publishing LLC.

Wu Y.,Central China Normal University | Wu Y.,Kashi Normal College | Zhang G.,Central China Normal University | Zhao L.,Kashi Normal College
Optical Engineering | Year: 2014

We propose a different type of asymmetric photonic crystal waveguide to achieve slow light with improved normalized delay-bandwidth product and low group velocity dispersion. The lateral symmetry of the proposed waveguide is broken by periodically shifting the two rows of air holes adjacent to the line defect. Under two simple different procedures of shifting air holes, the group indices of 41, 50, 68, and 114 with bandwidths over 14.9, 11, 7.8, and 4.7 nm, and the group indices of 43, 54, 73, and 124 with bandwidths over 13.9, 10.4, 7.1, and 4.3 nm around 1550 nm are obtained, respectively. Low-dispersion slow light propagation is confirmed by studying the relative temporal pulse-width spreading with the two-dimensional finite-difference timedomain method. © 2014 Society of Photo-Optical Instrumentation Engineers (SPIE).

Du Y.,Central China Normal University | Du Y.,Xinjiang Normal University | Zhang G.,Central China Normal University | Wu Y.,Central China Normal University | And 4 more authors.
Optical Fiber Technology | Year: 2013

It is proposed and demonstrated a design of 2-to-1 photonic data selector based on the cross-phase modulation in a highly nonlinear fiber. By using bidirectional configuration, this scheme has potentially advantages of cost effective and simple structure. The correct output logic function is obtained at 40 Gbit/s without using any additional input light beams. In addition, the output signals have a single spectrum component by reasonable selecting input signals wavelength, which is important for transmission and scalability. The dependences of performances on signal wavelength, pump power, the temporal relative position of pulses, as well as the OSNR and chirp of input signals are calculated and discussed respectively, showing impressive operation performance. This scheme could be a promising candidate for future ultrafast all-optical signal processing applications. © 2012 Elsevier Inc. All rights reserved.

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