Browsing by Author "Xu, Lin"

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Long-Reach Multicast High Split-Ratio Wired and Wireless WDM-PON Using SOA for Remote Upconversion
(2010-11-01)
Xu, Lin
;
Chow, Chi Wai
;
Tsang, Hon Ki
;
光電工程學系
;
Department of Photonics
We propose and experimentally demonstrate a cost-efficient hybrid gigabit wired and wireless long-reach and high split-ratio optical access network based on remote upconversion at the local exchange (LE). The scheme can deliver 40-GHz millimeter-wave wireless services supporting wavelength multicasting over 125-km standard single-mode fiber. A semiconductor optical amplifier (SOA) is used as the multiwavelength broadband optical upconverter and optical power amplifier inside the LE, and a high split-ratio of 512 can be supported. Wavelength multicasting can also be realized with conversion efficiency variation of within 1 dB over 15-nm wavelength range. The SOA has a gain with low polarization dependency and is able to realize multiwavelength operation based on four-wave-mixing for signal upconversion. Results show that the optical millimeter-wave signal distortion due to fiber chromatic dispersion can be significantly mitigated by using the proposed scheme. Expensive RF components are not required at the LE for signal upconversion because the SOA requires only dc bias. The polarization states of the input signals can be controlled at the head-end office; hence, polarization control in the LE may not be required. Error-free transmission for the wired signal was achieved and a power penalty of 2.3 dB was measured after 125-km transmission.
Optical mm-Wave Signal Generation by Frequency Quadrupling Using an Optical Modulator and a Silicon Microresonator Filter
(2009-01-01)
Xu, Lin
;
Li, Chao
;
Chow, C. W.
;
Tsang, Hon Ki
;
光電工程學系
By adjusting the direct current (de) bias on an electrooptic modulator to suppress the first-order sideband and subsequently using a double-waveguide micro-ring resonator to filter out the optical carrier, millimeter (mm)-wave signal was generated at a frequency of four times the 10-GHz local oscillator. A monolithic integrated silicon-based optical mm-wave signal generator by frequency quadrupling is proposed. A silicon integrated microresonator filter was fabricated and its design parameters are given. High extinction ratio optical mm-wave signal was obtained. The single sideband noise spectrum of the generated 40-GHz optical signal was measured, showing similar performance when compared with that generated by a radio-frequency synthesizer.
Rayleigh Backscattering Mitigation Using Wavelength Splitting for Heterogeneous Optical Wired and Wireless Access
(2010-09-01)
Chow, C. W.
;
Yeh, Chien Hung
;
Xu, Lin
;
Tsang, Hon Ki
;
光電工程學系
We propose and demonstrate a heterogeneous optical access network using wavelength-splitting at remote-node to mitigate the Rayleigh backscattering (RB) noises. Two continuous-wave carriers are generated from each laser for wired and wireless applications, respectively. Results show that the scheme can effectively mitigate RB noises.