Advanced Materials Research Vols. 760-762

Abstract: Under the development of society, the dissemination of information plays an increasingly significant role. How to achieve the goal of continually reducing the error rate and enhance the quality of communication and construct a highly reliable, efficient and high-speed Broadband Communication System is really a tough task. Here comes the FEC that is one particular type of error correction codes which is introduced to protect the process of data transmitting. In addition to a brief introduction to FEC, this article covers the categories of FEC and their applications along with comparisons and also describes the latest development of these error correction algorithms.

Abstract: Nowadays CO₂ laser has been regarded as the effective treatment methods of different kinds of cosmetology and dermatologic surgery. The second-degree scald is of frequent occurrence in people, but many methods on treat the second-degree scald are not good enough. Therefore, the process of second degree scald skin irradiated by the CO₂ laser was monitored in the study. The second-degree scald of mice models were divided into two groups in order to contrastively observe the effect of CO₂ laser on treating scald. Skin detector associating with the histopathologic examination were used to observe the changes of skin texture and pathologic morphology structure. Meanwhile the healing time was recorded about the two groups. The texture of skin surface irradiated CO₂ laser was more glossy and distinct after healing, and the healing time was much faster as well. It was good agreement between skin detector images and histopathological architecture. The result suggests the CO₂ laser can significantly cure the the second-degree scald.

Abstract: An experimental apparatus for the analysis of biological cells light scattering in liquid suspensions has been presented. Characterization is based on the scattering of a monochromatic laser beam by particles [which can be inorganic, organic, or biological (such as animal cells and bacteria)] and on the strong relation between the light-scattering pattern and the morphology and refractive index of the particles. In order to study light scattering in biological cells close to the actual situation, we focus on non-spherical particles in the cell-culture medium. Finally, we demonstrate the light scattering results of bovine kidney cells suspended in the cell-culture medium, and compares then with the simulated results.

Abstract: Progress of gain-switched Tm-doped fiber lasers is reported. Different pump schemes including 1μm, 790nm, 1.6μm, 1.9μm and combined pump are described in detail. Comparisons among these different pump schemes are given. Discussions are made and other possible pump schemes are proposed.

Abstract: A fully integrated 10-Gb/s optical receiver analog front-end (AFE) design that includes a transimpedance amplifier (TIA) and a limiting amplifier (LA) is demonstrated to require less chip area and is suitable for both low-cost and low-voltage applications. The AFE is stimulation using a 0.18μm CMOS process. In order to avoid off-chip noise interference, the TIA and LA are dc-coupled on the chip instead of ac-coupled though a large external capacitor. The tiny photo current received by the receiver AFE is amplified to voltage swing of 400. The results indicate that, with a photodiode parasitic capacitance of 500fF and the bonding pad parasitic capacitance of 200fF between which a 2-mm bond wire is inserted at the input node, the AFE provides a conversion gain of up to 89.21 dB and 3 dB bandwidth of 9.78 GHz. Operating under a 1.8V supply, circuit power dissipation is 95 mW and its sensitivity is 18.5μA for BER of 10^-12

Abstract: An inductorless circuit for limiting amplifiers is present. With the third-order interleaving active feedback, the bandwidth of this circuit could be enhanced while keeping a suppressed gain. The amplifier is simulation in a 0.18μm CMOS technology. The results show that the circuit consuming a DC power of 90mW with a 1.8V supply voltage, its voltage gain is about 42.6dB, the 3dB bandwidth of the circuit is 10.96GHz.The limiting amplifier circuit can be used in the STM-64 optical fiber communication system.

Abstract: An acousto-optic Q-switched pulse fiber laser was presented, and the output power of 20.3W was obtained by using the one-stage Ytterbium-doped double-cladding fiber amplification. The repetition frequency of the pulse fiber laser was tunable in the range of 20-60kHz. We obtained the pulse output with pulse width of 113ns, peak power of 9kW and the average power of 20.3W, when the repetition frequency was 20kHz. We also measured pulse width at different repetition rate and analyzed pulse waveform.

Abstract: This electronic document Elaborated on the work principle of the detection system of watercrafts traffic volume based on laser sensation, and introduced the key technologies and concrete realization in the application of fairway intelligent management.

Abstract: The spectral efficiency and bit-error-rate (BER) of phase encoding optical code division multiple access (OCDMA) systems is evaluated, coherent time-spreading (TS) and spectral phase encoding (SPE) OCDMA systems are considered. The results indicate that SPE-OCDMA has better tolerance to performance degradation due to receivers bandwidth limitation than TS-OCDMA system, while for the practical en/decoders with implementable longest code length, TS-OCDMA can yield a spectral efficiency advantage over SPE-OCDMA systems.

Abstract: InAs/GaSb superlattice in infrared detector was grown on GaSb substrates by molecular beam epitaxy technique. Using inductively coupled plasma (ICP) etching technique and Cl₂/Ar etching gas, the smooth mesa of the device was formed. The influence of etching time, Cl₂ percent and RF power on the etching rate and the surface morphology of InAs bulk, GaSb bulk materials and superlattice were studied. It showed that the etching rate of InAs was lower than that of GaSb and the etching surface was smooth at Cl₂ in the range of 20%~40%. The results will benefit to forming ohm contact and decrease surface leakage current in the photovoltaic detector.