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Impact of Polarization Mode Dispersion on High-Speed Optical Codes

Rao Min,Sun Xiaohan,Zhang Mingde

Strategic Study of CAE 2002, Volume 4, Issue 11, Pages 67-70

Abstract:

The first and second-order polarization mode dispersion (PMD) effect on the performance of 10 Gbit/s and 40 Gbit/s systems is studied. The statistical behavior of PMD is considered by simulating the nonreturn-to-zero (NRZ) and return-to-zero (RZ) pulses distortion and the system's Q-factor based on principal states of polarization (PSP) theory. It is found that the effect of PMD is significant in higher bit rate systems and the second-order PMD cannot be neglected. Furthermore, the RZ format is more tolerant to PMD than is the NRZ format, and the system performance is improved if the input pulses are appropriately chirped.

Keywords： polarization mode dispersion (PMD) non-return-to-zero (NRZ) return-to-zero (RZ) frequency chirp

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Grazing incidence polarized light imaging of footwear prints Regular Article

Xin-yi Bi, Rui-fang Han, Ran Liao, Wu-sheng Feng, Da Li, Xue-jie Zhang, Hui Ma,liao.ran@sz.tsinghua.edu.cn

Frontiers of Information Technology & Electronic Engineering 2019, Volume 20, Issue 11, Pages 1543-1550 doi: 10.1631/FITEE.1800383

Abstract: Footwear prints are important evidence in criminal investigation. They represent changes in the surface morphology due to disturbance to fine distributions. Existing non-contact optical detection methods usually measure the light intensity contrasts between the footwear prints and the ground, which can be enhanced by grazing incident illumination. We take images of footwear prints on different types of floors using a commercial single lens reflex color camera. Results show that adding linear polarizers in front of the camera lens and light source improves the contrast of footwear print images. The best contrasts are achieved in degree of linear . In addition, the three-color channels of the camera can be used to examine the spectral features of the images. According to the experimental results, the best contrast is obtained at the blue channel. The current work shows that grazing incidence polarized light imaging can effectively enhance the contrast of the footwear prints against the floors, which would help obtain footwear evidence in criminal investigation.

Keywords：偏振；图像增强；散射；粒子

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Polarizationmultiplexing based duplex radio-over-fiber link for millimeterwave signal transmission to a ring of multiple radio access units None

Tayyab MEHMOOD, Hina QAYYUM, Salman GHAFOOR

Frontiers of Information Technology & Electronic Engineering 2019, Volume 20, Issue 2, Pages 300-306 doi: 10.1631/FITEE.1700056

Abstract:

A radio-over-fiber (RoF) distributed antenna system (DAS) architecture is proposed, where millimeter wave (mm-wave) signals are transmitted to four different radio access units (RAUs) arranged in a ring topology. The proposed architecture transmits duplex data of 128 Mb/s to each RAU in both downlink (DL) and uplink (UL) directions. The radio frequency (RF) signals are transmitted by polarization multiplexing a multi-wavelength source. Millimeter-wave signals at a frequency of 25 GHz are generated at each RAU using remote heterodyne detection. The proposed architecture provides increased coverage while maintaining good bit error rate (BER) results.

Keywords： Radio over fiber Millimeter wave Radio access units