A.S. Xu

Peking University, Peping, Beijing, China

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Publications (5)3.11 Total impact

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    ABSTRACT: Fibre nonlinearity mitigation of non-return-to-zero on-off keying (NRZ-OOK) signals with diverse-vestigial-sideband (DVSB) filtering maximum likelihood sequence estimation (MLSE) is demonstrated by experiments and simulations, in which DVSB filtering is realised with a Mach-Zehnder (MZ) filter. In a 10.709-Gbit/s NRZ-OOK system, experimental results show that, at a fixed optical signal-to-noise ratio, the Q -factor is improved significantly with DVSB-MLSE compared to that with conventional MLSE. Simulations reveal that the performance of DVSB-MLSE can be further improved by optimising the parameters of DVSB filters for different launch powers.
    Electronics Letters 06/2010; · 1.04 Impact Factor
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    ABSTRACT: Chromatic dispersion compensation of non-return-to-zero on-off keying (NRZ-OOK) signals with a diverse-vestigial-sideband-filtering feed forward equaliser and a decision feedback equaliser (DVSB-FFE-DFE) is presented, in which diverse vestigial sideband (VSB) filtering is realised with a Mach-Zehnder (MZ) filter. In a 10.709 Gbit/s NRZ-OOK system, experiment results show that the standard singlemode fibre transmission distance at 3 dB optical signal-to-noise ratio penalty with DVSB-FFE-DFE is doubled, compared to that with conventional FFE-DFE.
    Electronics Letters 08/2009; · 1.04 Impact Factor
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    ABSTRACT: A 42.8 Gbit/s NRZ transmitter based on electro-absorption modulation (EAM) is demonstrated experimentally in a transmission system over 1200 km standard singlemode fibre. The combined effect of positive chirp in the EAM transmitter and the second-order dispersion compresses the pulse after transmission, which leads to better performance
    Electronics Letters 02/2007; · 1.04 Impact Factor
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    ABSTRACT: We report on a novel micro torsion mirror actuated by a compound electrostatic driving structure. The compound driving structure is made up of a planar plate drive and a vertical comb drive. The device is fabricated in SOI substrate by using a bulk-and-surface mixed silicon micromachining process. As demonstrated by experiment, the novel driving structure can actuate the mirror to achieve large-range continuous rotation as well as spontaneous 90° rotation induced by the pull-in effect in a voltage control fashion. The continuous rotating range of the micro torsion mirror is increased to about 46° at an increased threshold voltage. The measured threshold voltage ranges of the mirrors with torsion springs of 1 μm and 0.5 μm in thickness are 390–410 V and 140–160 V, respectively. Theoretical modeling is carried out to compare with the experiment. The optical insertion loss has also been measured to be −1.98 dB when the mirrors serve as digital optical switches in a 2 × 2 array form.
    Sensors and Actuators A: Physical. 01/2007;
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    ABSTRACT: A novel hybrid electrostatic actuator made up of a planar plate drive and a vertical comb drive is developed for actuating torsional micromirror. The device consisting of the actuator and an into-plane tiltable mirror is fabricated in SOI substrate based on bulk-and-surface mixed silicon micromachining. As demonstrated by experiment, the novel actuator can drive the mirror to achieve large-range continuous tilting as well as spontaneous 90° tilting induced by the pull-in effect in a voltage control fashion. The continuous tilting range of the micromirror is increased to about 46°. Both theoretical modeling and experimental observations indicate that, accompanying the increase in the continuous tilting range, the yielding voltage increases. The device has also been used as a mirror switch in an optical system, and the optical insertion loss is measured to be -1.98 dB.
    Sensors, 2005 IEEE; 01/2005