C. H. Chuang

Full-duplex DOCSIS/WirelessDOCSIS fiber-radio network employing packaged AFPM-based base-stations

The simultaneous wireline (600 MHz) and wireless (5.5 GHz) transmission of data over cable service interface specification (DOCSIS) signals in a hybrid fiber-radio access network is presented. The DOCSIS signal wireless replica is generated by means of an optical harmonic up-conversion technique based on a dual-drive Mach-Zehnder modulator. The optical signal is fed to a base station (BS) where a packaged asymmetric Fabry-Pe/spl acute/rot modulator/detector acts simultaneously as a photodetector and an optical modulator. At the BS, the DOCSIS signals can be fed either to a wireline or a wireless access network, in a highly flexible approach. Full-duplex operation has been demonstrated for both access types, including indoor wireless transmission.

Full-Duplex DOCSIS/WirelessDOCSIS Fiber–Radio Network Employing Packaged AFPMs as Optical/Electrical Transducers

A hybrid fiber-radio access network architecture for simultaneous wireline and wireless transmissions of data-over-cable service interface specification (DOCSIS) signals is presented. An all-optical harmonic up-conversion technique using a dual-drive Mach-Zehnder modulator provides the downstream optical signal modulated not only at the intermediate frequency in the 600- to 900-MHz band for wireline transmission but also at the up-converted frequency in the 5.45- to 5.75-GHz band for wireless transmission. An InGaAsP/InGaAsP multiple-quantum-well asymmetric Fabry-Perot modulator/detector has been designed, fabricated, and packaged and has been employed in the base station (BS) as an optical/electrical transducer, simultaneously providing the functions of optical intensity modulation and photodetection. At the BS, the DOCSIS signals are recovered at the wireline and wireless frequencies for the respective feeding of a cable access network or a fixed wireless access network in a highly flexible approach. Full-duplex operation has been demonstrated for both access types in an indoor laboratory environment. In a subsequent small-scale field trial, real-life Internet traffic provided by a local community antenna television system operator has been transported over the present hybrid fiber-radio access network architecture, and simultaneous transmission of both DOCSIS and digital television signals has also been performed.

High-Speed 1.56-μm Multiple Quantum Well Asymmetric Fabry-Perot Modulator/Detector (AFPMD) for Radio-Over-Fibre Applications

We have designed and fabricated air-bridged optical modulator/detectors with modulation bandwidth exceeding 15GHz, the highest yet reported for InGaAsP/InGaAsP MQW AFPMDs. Wavelength dependence of the modulated output power at microwave frequencies is reported for the first time and the wide optical bandwidths (> 17nm) so measured suggest that the AFPMD can be used with low-cost uncooled CWDM lasers in radio-over-fibre applications.

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.

Enhanced linear dynamic range of asymmetric Fabry-Pe/spl acute/rot modulator/detector

An InGaAsP multiple-quantum-well asymmetric Fabry-Pe/spl acute/rot modulator/detector has been developed for radio-over-fiber systems. The measured bandwidth is more than 6 GHz and the total insertion loss is 7.1 dB. The property of nonlinearity and spurious-free dynamic range (SFDR) has been studied theoretically. By optimizing the operation optical wavelength and bias voltage based on the numerical simulation, fifth-order nonlinearity dominates the intermodulation distortion and an SFDR of 101 dB/spl middot/Hz/sup 4/5/ has been achieved experimentally.

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.

An EBG enhancement to patch array antenna with integrated optical transducer

In this paper, a circular polarized two-by-two patch array is designed and manufactured with the enhancement of spiral EBG elements. The design procedure of the EBG elements is described, as well as the simulated and measured antenna performance. More compact in size comparing with traditional mushroom structure, the spiral element with via also tackles the circular polarized field. The mutual coupling levels of the array are significantly reduced by more than 5 dB at 5.24 GHz, while the radiating element spacing remains at half wavelength in free space.

Experimental Demonstration of Full-Duplex DOCSIS Signal Transmissions over a Wireline/Wireless-Fibre Access Network

A fibre-radio access network architecture for simultaneous wireline and wireless transmissions of data over cable service interface specification (DOCSIS) signals is presented. An all-optical harmonic up-conversion technique using a dual-drive Mach-Zehnder modulator (DD-MZM) is employed at the central station while an InGaAsP/InGaAsP multiple quantum well (MQW) asymmetric Fabry-Perot modulator/detector (AFPM) functions as a single optical/electrical transducer performing optical intensity modulation and photodetection simultaneously at the base station. Full-duplex operation is demonstrated for both access types in an indoor laboratory environment as well as in a small-scale outdoor field trial

Intermodulation Distortion Suppression in a Full-Duplex Radio-over-Fibre System Employing Asymmetric Fabry-Perot Modulator/Detector

The property of intermodulation distortion in a full-duplex radio-over-fibre system with Asymmetric Fabry-Perot Modulator/Detector was investigated. By employing the balanced RF input powers, intermodulation distortion was suppressed and a SFDR of 99dB. Hz2/3 has been achieved.

Low-cost packaging of a reflective electroabsorption modulator/detector with optimized spurious free dynamic range

A packaged high speed reflective electroabsorption transceivers for radio-over-fiber applications is demonstrated. The transceiver, an AFPMD (Asymmetric vertically addressed Fabry-Perot Modulator/Detector), is successfully packaged into a standard module, originally intended for 10 Gbit/s Ethernet detectors. The packaging process and the electrical, optical and thermal performance of the packaged component are presented. A bandwidth of 6 GHz, a total reflective optical coupling loss of 7.1 dB and a responsitivity of 0.14 mA/mW are accomplished. By optimizing the operation optical wavelength and bias voltage, fifth-order nonlinearity dominates the intermodulation distortion and a spurious free dynamic range (SFDR) of 101dB.Hz4/5 at 5.554GHz can be achieved experimentally.