Browsing by Author "Xu, L."

Now showing 1 - 9 of 9

40-Gb/s Upstream Transmitters Using Directly Modulated 1.55-mu m VCSEL Array for High-Split-Ratio PONs
(2010-03-01)
Chow, C. W.
;
Xu, L.
;
Yeh, C. H.
;
Tsang, H. K.
;
Hofmann, W.
We propose and demonstrate a 40-Gb/s symmetric passive optical network with a high split-ratio of 64. The upstream 4 x 10 Gb/s signal is produced by using a directly modulated, uncooled 1.55 mu m monolithic integrated vertical-cavity surface-emitting laser array. The downstream signal is a single-channel 40-Gb/s dark-return-to-zero (DRZ) data, broadcasting information to different optical networking units (ONUs). As the ONU is cost-sensitive, we also demonstrate, by means of simulations, using a 12-Gb/s receiver at the ONU to receive the 40-Gb/s DRZ downstream signal.
Bidirectional colorless wired and wireless WDM-PON with improved dispersion tolerance for radio over fiber
(2011-07-01)
Xu, L.
;
Chow, C. W.
;
Tsang, H. K.
;
光電工程學系
;
Department of Photonics
We propose and demonstrate a bidirectional transmission, hybrid wired and wireless access network based on subcarrier modulation (SCM) techniques. The scheme simultaneously enables the dispersion-tolerant transmission of millimeter (mm)-wave signals for use in wireless access networks, downstream baseband signals for optical wired access networks, and optical continuous-wave (CW) carriers for use in upstream data remodulations. Error-free transmissions through a 25-km length of single mode fiber (SMF) for both the downstream baseband and the remodulated upstream signals are confirmed by bit-error-rate (BER) measurements. The dispersion tolerance of the radio-over-fiber (RoF) signal is assessed using numerical simulations. (c) 2011 Elsevier B.V. All rights reserved.
Bidirectional ROF Transmission and Signal Remodulation Using Separate Optical Clock Distribution to Mitigate Signal Distortions
(2009)
Chow, C. W.
;
Xu, L.
;
Yeh, C. H.
;
Wang, C. H.
;
Shih, F. Y.
We demonstrate a bidirectional ROF system using a separate optical-clock distribution to mitigate signal-fading and code time-shifting. Error-free signal remodulation using downlink DPSK and uplink OOK was achieved in a 20-km reach ROF system. (C)2009 Optical Society of America
Frequency Quadrupling of Phase Modulated Signals
(2010-01-01)
Xu, L.
;
Li, C.
;
Chow, C. W.
;
Chen, X.
;
Wong, C. Y.
we demonstrate optical up-conversion with frequency quadrupling using an optical phase modulator and a flat-top silicon microresonator filter by beating two second order sidebands at photodetector. 14GHz signal was achieved using 3.5GHz RF components.
Mitigation of Signal Distortions Using Reference Signal Distribution With Colorless Remote Antenna Units for Radio-Over-Fiber Applications
(2009-11-01)
Chow, C. W.
;
Xu, L.
;
Yeh, C. H.
;
Wang, C. H.
;
Shih, F. Y.
In this paper, we propose and demonstrate a bidirectional radio-over-fiber (ROF) system using a reference signal distribution. In order to minimize the radio-frequency (RF) signal attenuation as well as limit the transmit power to moderate levels, small cell size, or picocell is used in the ROF system. This will result in the need of many base stations (BSs) to provide sufficient network coverage. Because of this, colorless remote antenna unit (RAU) with optical carrier generated and distributed from the head end (HE) is employed. Experimental results show that error-free signal transmission and remodulation using downstream differential phase shift keying (DPSK) and upstream ON-OFF keying (OOK) is achieved in a 20-km reach ROF system. Experimental characterization of the reflective semiconductor optical amplifier (RSOA)-based remodulation unit is also performed. Numerical simulation is performed to compare the proposed scheme with several conventional optical millimeter-wave (mm-wave) schemes, including double sideband (DSB), optical carrier suppression (OCS), and single sideband (SSB). Results show that the proposed scheme could be a potential candidate to mitigate signal distortions due to signal fading and code time shifting.
Optical frequency doubling for multichannel radio-over-fibre system based on integrated phase modulator and silicon coupled microring notch filter
(2009-06-18)
Xu, L.
;
Li, C.
;
Tsang, H. K.
;
Chow, C. W.
;
光電工程學系
An integrated optical millimetre-wave signal generator based on a coupled microring resonator, which doubles the frequency of the electrical signal driving a phase modulator, is proposed and experimentally demonstrated for future radio-over-fibre systems. The coupled microring notch filter was fabricated on a silicon-on-insulator wafer. A high extinction ratio optical millimetre-wave signal was obtained.
Optical frequency doubling for multichannel radio-over-fibre system based on integrated phase modulator and silicon coupled microring notch filter
(2009-06-01)
Xu, L.
;
Li, C.
;
Tsang, H. K.
;
Chow, C. W.
;
光電工程學系
An integrated optical millimetre-wave signal generator based on a coupled microring resonator, which doubles the frequency of the electrical signal driving a phase modulator, is proposed and experimentally demonstrated for future radio-over-fibre systems. The coupled microring notch filter was fabricated on a silicon-on-insulator wafer. A high extinction ratio optical millimetre-wave signal was obtained.
Optical frequency doubling for multichannel radio-over-fibre system based on integrated phase modulator and silicon coupled microring notch filter
(2009-06-01)
Xu, L.
;
Li, C.
;
Tsang, H. K.
;
Chow, C. W.
;
光電工程學系
An integrated optical millimetre-wave signal generator based on a coupled microring resonator, which doubles the frequency of the electrical signal driving a phase modulator, is proposed and experimentally demonstrated for future radio-over-fibre systems. The coupled microring notch filter was fabricated on a silicon-on-insulator wafer. A high extinction ratio optical millimetre-wave signal was obtained.
Using Wavelength Splitting at the Remote Node to Mitigate Rayleigh Backscattering for Optical Wired and Wireless Access Networks
(2010)
Chow, C. W.
;
Xu, L.
;
Shih, F. Y.
;
Wu, Y. F.
;
Yeh, C. H.
We demonstrate an optical wired and wireless access network using wavelength-splitting (WS) at remote-node. A pair of CW carriers is generated from each laser source for wired and wireless applications respectively for effective Rayleigh-backscattering mitigation. (c) 2010 Optical Society of America