Ruben Alemany

100-GHz Wireless-Over-Fiber Links With Up to 16-Gb/s QPSK Modulation Using Optical Heterodyne Generation and Digital Coherent Detection

In this letter, a novel technique for direct conversion of an optical baseband quadrature phase-shift keying (QPSK) signal to a millimeter-wave wireless signal and subsequent signal demodulation is reported. Optical heterodyne mixing of the optical baseband QPSK signal with a free-running unmodulated laser for the wireless signal generation is employed. To correct for the phase and frequency offset originating from the heterodyne mixing of the two free-running lasers, wireless signal demodulation based on optical coherent detection in combination with baseband digital signal processing is implemented. As a proof of concept, 5-Gb/s amplitude-shift keying and up to a 16-Gb/s QPSK wireless signal in the band of 75-110 GHz was generated and successfully demodulated. All-photonic millimeter-wave wireless signal generation and digital coherent detection at baud-rate are employed without complex optical phase-locked loop.

Radio-Frequency Transparent Demodulation for Broadband Hybrid Wireless-Optical Links

A novel demodulation technique which is transparent to radio-frequency (RF) carrier frequency is presented and experimentally demonstrated for multigigabit wireless signals. The presented demodulation technique employs optical single-sideband filtering, coherent detection, and baseband digital signal processing. Multigigabit wireless signal demodulation of 1.25-Gbaud quadrature phase-shift-keying modulated data at 40- and 35-GHz RF carrier frequency is experimentally demonstrated using the proposed demodulation scheme.

Radio frequency transparent demodulation for broadband wireless links

Novel demodulation technique for radio over fiber systems, transparent to RF carrier frequency, employing coherent detection and baseband digital signal processing is presented for the first time. Multi-gigabit signal demodulation at 40 GHz RF is demonstrated.

16 Gb/s QPSK Wireless-over-Fibre link in 75–110GHz band employing optical heterodyne generation and coherent detection

We report on the first demonstration of QPSK based Wireless-over-Fibre link in 75–110GHz band with a record capacity of up to 16Gb/s. Photonic wireless signal generation by heterodyne beating of free-running lasers and baud-rate digital coherent detection are employed

UMTS radio-over-fiber pico-cell interconnection employing low-cost VCSELs and multi-mode fibre

This paper investigates experimentally the suitability of low-cost vertical cavity surface emitting lasers (VCSEL) for radio-over-fibre transmission of UMTS signals. Three directly-modulated VCSEL configurations are investigated: Multi-mode VCSELs operating at 850 nm and 1300 nm respectively in multi-mode fibres (MMF), and single-mode VCSELs operating at 1310 nm with standard single-mode fibre (SSMF). In the later case, the performance of directly-modulated distributed-feedback (DFB) lasers is also reported for comparison. The experimental results demonstrate that UMTS radio-over-fibre is feasible at distances exceeding 1 km and 2 km on MMF with multi-mode VCSELs operating at 850 nm and 1300 nm, respectively. Transmission distances exceeding 25 km can be obtained with the single-mode VCSELs in SSMF. In this later case, the transmission performance is comparable to a directly-modulated distributed feedback laser source, but at much lower cost.

Photonic vector demodulation of 2.5 Gbit/s QAM modulated wireless signals

In this paper, a technique for demodulation of vector modulated signals like QAM, using photonic techniques is presented. The photonic vector demodulator is capable of converting broadband wireless QAM signals into independent inphase and quadrature optical baseband signals. Experimental demonstration of demodulation of 2.5 Gbit/s QAM modulated 20 GHz carrier is presented. Bit error ratio of the demodulated-I and -Q optical baseband signals is measured and an error free demodulation achieved. A receiver sensitivity of -26.5 dBm and -27 dBm were measured for the I and Q signals respectively.

Full-duplex Wireless GbE Field Trial Employing Radio-over-Fiber Technologies

A full-duplex radio-over fiber system for the transmission of Gigabit Ethernet signals in the mm-wave band has been demonstrated under a field trial, providing redundant connections and point-to-point wireless extension of optical GbE networks.

Bidirectional Transmission of WiMedia-Compliant UWB Over 100-m Perfluorinated Graded-Index Plastic Optical Fiber

We present the first experimental demonstration of full-duplex, bidirectional transmission of WiMedia-compliant ultra-wideband (UWB) signals at 200 Mb/s over 100-m perfluorinated graded-index plastic optical fiber (POF) with 50-μm core diameter. Error vector magnitude penalties of 1.2 dB and 2.1 dB are achieved for up- and downlink transmission, respectively.

Differential phase modulated hybrid wireless/wireline links based on Optical Phase Modulation and Demodulation

Wireless links based on optical DxPSK and passive optical interferometer based demodulation is presented and a 5 Gb/s 60 GHz DPSK wireless signal generation and demodulation experimentally demonstrated.

Multi-gigabit wireless over fibre links employing photonics downconversion and digital coherent detection

Wireless access networks are demanding multi-gigabit capacities to cope with growing bandwidth demands. We present results showing that digital coherent detection and photonic downconversion support wireless over fiber links with capacities approaching baseband optical links.