Electrical and Electronic Engineering - Research Publications

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    A compact silicon grating coupler based on hollow tapered spot-size converter
    Asaduzzaman, M ; Bakaul, M ; Skafidas, E ; Khandokar, MRH (NATURE PORTFOLIO, 2018-02-07)
    A new compact silicon grating coupler enabling fibre-to-chip light coupling at a minimized taper length is proposed. The proposed coupler, which incorporates a hollow tapered waveguide, converts the spot-size of optical modes from micro- to nano-scales by reducing the lateral dimension from 15 µm to 300 nm at a length equals to 60 µm. The incorporation of such a coupler in photonic integrated circuit causes a physical footprint as small as 81 µm × 15 µm with coupling efficiency and 3-dB coupling bandwidth as high as 72% and 69 nm respectively.
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    Simplification of millimeter-wave radio-over-fiber system employing heterodyning of uncorrelated optical carriers and self-homodyning of RF signal at the receiver
    Islam, AHMR ; Bakaul, M ; Nirmalathas, A ; Town, GE (OPTICAL SOC AMER, 2012-02-27)
    A simplified millimeter-wave (mm-wave) radio-over-fiber (RoF) system employing a combination of optical heterodyning in signal generation and radio frequency (RF) self-homodyning in data recovery process is proposed and demonstrated. Three variants of the system are considered in which two independent uncorrelated lasers with a frequency offset equal to the desired mm-wave carrier frequency are used to generate the transmitted signal. Uncorrelated phase noise in the resulting mm-wave signal after photodetection was overcome by using RF self-homodyning in the data recovery process. Theoretical analyses followed by experimental results and simulated characterizations confirm the system's performance. A key advantage of the system is that it avoids the need for high-speed electro-optic and electronic devices operating at the RF carrier frequency at both the central station and base stations.
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    Fiber-Wireless Networks and Subsystem Technologies
    Lim, C ; Nirmalathas, A ; Bakaul, M ; Gamage, P ; Lee, K-L ; Yang, Y ; Novak, D ; Waterhouse, R (IEEE-INST ELECTRICAL ELECTRONICS ENGINEERS INC, 2010-02-15)