Search

A novel silicon- As 2 S 3 slab/slot waveguide with an ultra-broadband (~5500nm) and low dispersion (from -7 and +19ps/nm/km) is proposed. As the slab introduced, the novel waveguide with three zero-dispersion wavelengths is obtained in the mid-infrared wavelength region from 3020 to 8500nm. The silicon- As 2 S 3 slab/slot waveguide can be used to generate ultra-board supercontinuum ranging from 1.7 to 10.6μm. The proposed waveguide has great potential for ultra-broadband signal processing applications in near-infrared and mid-infrared region.

Weight distribution of code is very important for error correction in the use of Turbo coding program in optical fiber communication. Input sequence need to pass convolutional encoder, Therefore, it is necessary that the weight of the output should be kept as large as possible. Although the interleaver can help to improve the output code weight, the higher the complexity of interleaving, the iterative decoding will be more complex. In consequence, we can judge the weight of the input data before encoding. Invert all bits when the weight of the code is less than a certain value of its length. It can improve the weight of the code through such a simple way and reduce the complexity of the interleaver at the same time.

In the paper, we propose a new method, namely Random Filtering Mapping (RFM), through which the peak-to-average power ratio (PAPR) of the Generalized frequency division multiplexing (GFDM) signal is reduced. Then, the improved signal is transmitted through the Radio Over Fiber (ROF) system of Single SideBand (SSB) modulation and optical fiber of 60Km. The simulation results show that the PAPR of the RFM-GFDM signal is about 5dB lower than the original GFDM signal. In addition, the EVM of the RFM-GFDM signal is about 0.5%–5% lower than the original GFDM. The proposed method greatly improves the performance of the GFDM signal in ROF system, which is a better choice for transmission.

We demonstrated a dense sub-carrier uniform division labeling transmission system by using MATLAB software. The simulation results indicated that dense sub-carrier uniform division labeling has a good advantage over that ordinary OFDM system, and the signals at a bit rate 50Gbit/s have a good performance which is more than 10 when OSNR is equal to 25dB over 1000km optical fiber channel which only concerns the influence of polarization-mode dispersion.

This article reported on strain-compensated quantum well structure for AlGaInAs/InP and used the ALDS to do numerical simulation for lasers. It can be concluded that the introduction of appropriate strain opposite to well layer strain in barrier layer can improve the energy band structure of quantum wells and the limitation carriers. After testing, the laser had a low threshold current of 13.4mA and a slope efficiency of 0.54W/A at 25□. The quality of the quantum well has been improved by optimizing its strain and adopting strain-compensated methods.

The convergence of optical and wireless network has led to the trend of future access network . Under the study of Software Defined Radio Access Network(SD-RA) and Soft Frequency Reuse(SFR) system model, this paper presents a new inter-cell interference suppression algorithm of SD-RA network. The paper also summarizes and analyses the difference between the SFR based on coordinate multi-point transmission (CoMP) and SD-RA. The computer simulation results show that the inter-cell interference suppression algorithm can bring about 5dB SINR (Signal to Interference plus Noise Ratio) gain.

Design and fabrication of multi-wavelength 1.3µm AlGaInAs/InP distributed feedback (DFB) laser array for analogy radio-over-fiber (RoF) system is proposed. The performance of the DFB laser such as high power, low noise, wide modulation bandwidth, high linearity has to be improved to meet the increase demand of the analogy RoF system. Here, we designed the structure of the MQWs to increase internal quantum efficiency and decrease the noise, optimized the parameter of the DFB grating to obtain high SMSR, and utilized BCB RWG to broaden 3dB bandwidth. A 4-channel multi-wavelength DFB laser array proposed was fabricated. Single longitude mode (SLM) operation was obtained with SMSR>46dB for all the lasers. The experimental results of the spectra have good agreement with simulation results. The typical slope efficiency was 0.445mW/mA. And the typical OCS and CTB of the laser diode are −66.3dB and −68.1dB, respectively. The 3dB bandwidth of the directly modulation can reach 15GHz. The linearity is high. The proposed multi-wavelength DFB laser array can be a promise candidate component for RoF system for multi-band and multi-service.

We have demonstrated generation and transmission of the 40GHz dual-tone optical millimeter (mm)-wave by quadrupling the 10GHz radio frequency local oscillator via a single dual-electrode 10GHz Mach-Zehnder modulator. The transmission performance of two different data modulation formats are discussed based on the transmission function of the dispersive fiber theoretically and then verified by simulation. Conclusion is given that, the transmission distance with dual tone data modulation is limited because of the sidebands walk off effect caused by the fiber dispersion. The bit walk off effect can be eliminated and transmission distance can be extended greatly for single tone data modulation.

This article used the event study method to study the sample stock of shang hai stock exchange, the research indicated that the block trading paid certain influence on the stock price, as the capital size of stock and the market environment change, the result will different.

Because of the widespread application of deep sub-micron and multilayer routing techniques, the interconnection parasitic influence has more and more effect on the performance of VLSI circuits. Parallel direct boundary element calculation of three-dimensional (3-D) resistance and capacitance is an important method for fast extraction. In this paper, a parallel algorithm to implement linear boundary element calculation using PVM (Parallel Virtual Machine, distributed calculating software) is introduced. The hierarchical calculation scheme of the setup and solution processes of linear equations is discussed. At the end, the performance and workload balance of the algorithm are analyzed.