Tabassam Ismail

High-Dynamic-Range Wireless-Over-Fiber Link Using Feedforward Linearization

We demonstrate the implementation of feedforward linearization at 5 GHz, which is the highest operating frequency yet reported, with 500-MHz linearization bandwidth having at least 24-dB distortion suppression. Simultaneous reduction of 26-dB third-order intermodulation distortion and 7-dB laser-noise reduction is achieved at 5.2 GHz, leading to enhanced spurious-free dynamic range of 107 dB (1 Hz) in a directly modulated uncooled semiconductor laser for applications in wireless-over-fiber (WoF) systems. This paper also provides detailed analysis on feedforward, theoretical distortion reduction, criteria for component selection, and the effect of dispersion. The effectiveness of feedforward in a multichannel system is demonstrated at 5.8 GHz for fixed wireless systems, such as WiMAX. These results suggest that the feedforward-linearization arrangement can make practical multichannel and multioperator WoF systems.

Broadband Access Using Wireless Over Multimode Fiber Systems

With the growing need for low cost wireless over fiber systems the use of multimode fiber (MMF) has become of greater interest. The well known advantages of optical fiber as a transmission medium such as low loss, light weight, large bandwidth characteristics and small size make it the most flexible solution for transporting radio signals to remotely located antenna sites where coverage is required. To provide reliable indoor cellular and wireless local area network (WLAN) coverage without dependence on the radio penetration from outside base stations, it is highly desirable that the same MMF infrastructure be used to carry additional services between the equipment room and the remote antenna units around the building. One of the main benefits of using the wireless over fiber technique is the inherent transparency to the transported wireless signals. This allows configuring the system for a range of both wireless and cellular services to be combined to transmit simultaneously. Hence, it is highly desirable to invest in a multiservice broadband remoting infrastructure which is capable of handling both current and future RF systems. In this paper we present an overview of some of the latest technologies for wireless over multimode fiber systems.

Transmission of 37.6-GHz QPSK wireless data over 12.8-km fiber with remote Millimeter-wave local oscillator delivery using a bi-directional SOA in a full-duplex system with 2.2-km CWDM fiber ring architecture

Full-duplex 3.5-MSymb/s millimeter-wave quadrature-phase-shift-keying wireless data transmission over 12.8-km fiber transmission between a central station and base stations located on a 2.2-km coarse wavelength-division-multiplex fiber ring, with remote 40-GHz local oscillator delivery using a bidirectional semiconductor optical amplifier, is demonstrated experimentally. Successful transmission is achieved with 10.5% and 7.8% error vector magnitude values for the downlink and the uplink directions, respectively.

Interchannel distortion suppression for broadband wireless over fibre transmission using feed-forward linearised DFB laser

We describe the first transmission of triple 11 Msymb/s QPSK channels over 2.2 km SMF using a feed-forward linearised uncooled DFB laser achieving 11 dB interchannel distortion suppression and 10.5 dB power advantage compared to the non-linearised case.

Feed-Forward Linearised Uncooled DFB Laser in a Multi-Channel Broadband Wireless over Fibre Transmission at 5.8 GHz

We present the first experimental demonstration of a feed-forward linearised uncooled laser at 5.8 GHz in a wireless-over-fibre system for the transmission of multi-channel broadband 16 QAM and 64 QAM signals over 2.2 km of single mode fibre intended for wireless LAN applications. We demonstrate that with such a linearisation scheme, a reduction of 20 dB is achieved in the spectral re-growth caused by a strong adjacent channel. Significant reduction in the error vector magnitude and improved constellation and eye-diagrams were observed. Intermodulation distortion is reduced by 13 dB when two strong channels are at +10 dBm input level.

Transmission of Gb/s DPSK Millimeter-Wave Wireless Data Over Fiber Using Low-Cost Uncooled Devices With Remote 40-GHz Local Oscillator Delivery

We demonstrate the first millimeter-wave Gb/s transmission of broadband wireless signals using uncooled directly modulated lasers to give a low-cost solution. Data signals to and from the base station are distributed at intermediate frequencies for reduced chromatic dispersion together with a remote 40-GHz local oscillator signal for frequency upconversion/downconversion. Coarse-wavelength-division-multiplexing components are employed throughout the network allowing uncooled lasers and low cost filters to be used. Error-free transmission (BER < 10-9) has been achieved for the downlink and the uplink. The paper also provides detailed system link analysis together with simulation results.

IEEE 802.11a Data Over Fiber Transmission Using Electromagnetic Bandgap Photonic Antenna With Integrated Asymmetric Fabry–PÉrot Modulator/Detector

We report bidirectional link characterization and the first IEEE 802.11a wireless local area network (WLAN) data transmission using an electromagnetic bandgap (EBG) photonic antenna with an integrated InGaAs/AlInGaAs multiple quantum-well (MQW) asymmetric Fabry-Perot modulator/detector (AFPM). The dual-function AFPM performs as an optical intensity modulator on the uplink and as a conventional photodetector on the downlink in a single device. This new InGaAs/AlInGaAs AFPM device has also shown an improved modulation slope -dR/dV of 17%/V, where dR is the differential optical reflectance and dV is the differential terminal voltage, compared to the previously reported 6%/V achieved with an InGaAsP/InGaAsP MQW AFPM. Half-duplex IEEE 802.11a connection was successfully established between a laptop computer and the photonic antenna which in turn was connected via an optical fiber to a wireless access point. A maximum data throughput of 7 Mbps was achieved at 8-m separation between the laptop and the photonic antenna.

Integrated Photonic Electromagnetic Band Gap Antenna with InGaAs/AlInGaAs Multiple Quantum Well Asymmetric Fabry-Perot Modulator

We present the first bi-directional characterizations of a photonic electromagnetic band gap (EBG) antenna integrated with an InGaAs/AlInGaAs multiple quantum well (MQW) asymmetric Fabry-Perot modulator/detector (AFPM) operating in the 5 GHz band.

Wireless data transmission of IEEE802.11a signals over fibre using low cost uncooled directly modulated lasers

In this paper, we report the first fully bidirectional wireless data transmission of IEEE802.11a Wireless Local Area (WLAN) signals over fibre using uncooled directly modulated lasers thus providing a low cost solution. A successful connection of IEEE802.11a was established between a mobile unit and the remote base station (BS) which in turn was connected via an optical fibre to the wireless access point. A maximum data throughput of 20 Mbps and 18 Mbps was achieved at a 10 m separation distance between the mobile unit and the BS antenna in the uplink and downlink directions respectively. Results are also presented for the data throughput performance of the system with varying free space distance and the measured average throughput in both transmission directions.

Full-duplex wireless-over-fibre transmission incorporating a CWDM ring architecture with remote millimetre-wave LO delivery using a bi-directional SOA

We demonstrate the first full-duplex wireless-over-fibre transmission between a central station and a CWDM ring architecture with remote 40 GHz LO delivery using a bi-directional semiconductor optical amplifier.