Y. Le Guennec

New optical microwave up-conversion solution in radio-over-fiber networks for 60-GHz wireless applications

A new method for generating optical microwave mixing based on the optical phase modulation and the fiber chromatic dispersion is further investigated. A theoretical approach based on the analysis of the optical field spectrum has lead to the evaluation of the mixing power and optimal fiber lengths of 60-GHz radio-over-fiber (RoF) networks. Results have shown adaptable fiber lengths to match the network specifications

Optical Frequency Conversion for Millimeter-Wave Ultra-Wideband-Over-Fiber Systems

This letter investigates all-optical frequency conversion of ultra-wideband (UWB) signals for UWB-over-fiber up-link and down-link systems. An electrooptical Mach-Zehnder modulator is used in nonlinear regime to realize frequency up and down conversion of UWB rectangular pulse and monocycle. All-optical frequency up-conversion of rectangular pulse at 18 GHz generates undesired local oscillator centered in the up-converted UWB spectrum, whereas up-conversion of monocycle waveform exhibits a power spectrum density optimally fitting the UWB emission mask. Up and down conversions of UWB monocycle, using the same UWB-over-fiber system, have shown low distortion induced by the optical mixing process on the UWB monocycle.

Generation of 60-GHz MB-OFDM Signal-Over-Fiber by Up-Conversion Using Cascaded External Modulators

In this paper, we demonstrate multiband orthogonal frequency division multiplexing (MB-OFDM) transmission of quadrature phase shift keying (QPSK) modulation with 200-Mb/s bit rate by all-optical frequency up-conversion using external modulator for ultrawideband (UWB) applications to 60-GHz band radio-over-fiber (RoF) network. Error vector magnitude (EVM) measurements are used to evaluate the performance of our system and an EVM root mean square (rms) of 12.6% at 60 GHz is obtained with our technique and corresponds to bit error rate (BER) below 10-9, in compliance with standard requirements.

All-optical subcarrier frequency conversion using an electrooptic phase modulator

All-optical subcarrier frequency conversion using an electrooptic phase modulator in a radio-over-fiber link is proposed and demonstrated. The frequency mixing is implemented by an electrooptic phase modulator, to which a local oscillator frequency is applied. The phase modulation to intensity modulation conversion is realized by using a length of single-mode fiber, which serves as a dispersive device. A subcarrier frequency conversion from 3 to 11.5 GHz performed over a 25-km radio-over-fiber link is experimentally demonstrated.

Low-Cost All-Optical Up-Conversion of Digital Radio Signals Using a Directly Modulated 1550-nm Emitting VCSEL

The purpose of this letter is to demonstrate the extension of the modulation bandwidth of a single-mode vertical-cavity surface-emitting laser (VCSEL). The aim is to reach the radio-frequency range of wireless access networks such as ultrawide-band systems with low-cost solutions. In this letter, we have studied optical microwave mixing using nonlinear direct modulation of a VCSEL. First, the nonlinear behavior of the VCSEL near the threshold has been analyzed and explained based on frequency-mixing measurements made with continuous-wave signals. Then, we have experimentally demonstrated frequency up-conversion of a quaternary phase-shift-keying signal and a wireless local area network IEEE 802.11a signal.

Low-Cost Transparent Radio-Over-Fiber System for In-Building Distribution of UWB Signals

This paper investigates hybrid fiber-radio networks for in-building distribution of ultrawideband (UWB) signals, in order to extend UWB radio coverage area. An original multipoint to multipoint UWB-over-fiber system, proposed in the frame of BILBAO project, is presented and discussed. System link gain and noise figure are evaluated through theoretical analysis. A simulation model is used to study the impact of E/O transceivers nonlinearity on UWB signals. Experimental results show good agreement with simulation results. A high data rate file transfer, with UWB radio propagation and transmission over 100 m of multimode fiber, has been also successfully demonstrated.

Convergence of 60 GHz Radio Over Fiber and WDM-PON Using Parallel Phase Modulation With a Single Mach–Zehnder Modulator

We propose a converged radio over fiber and wavelength division multiplexing passive optical networks (WDM-PON) system compatible with wired and 60 GHz band wireless transmission by implementing two-band modulation with a single Mach-Zehnder modulator as parallel phase modulators. In this paper, broadband millimeter wave generation, which is compliant with the ECMA 387 standard, and 2.5 Gbps baseband transmission, which feeds up the requirement of fiber-to-the-home, are simultaneously realized after 25 km long optical fiber transmission. Furthermore, the interference between RF and baseband modulations is theoretically and experimentally investigated. The RF modulation impacts to the baseband signal for different RF modulation formats are deeply investigated.

Optical Distribution and Upconversion of MB-OFDM in Ultrawide-Band-Over-Fiber Systems

Broadband radio-over-fiber networks are raising great interest for intrabuilding distribution and signal processing of ultrawide-band (UWB) signals. In this paper, a unique optical system based on an external modulator biased either in linear or nonlinear regime has been used to realize both distribution of multiband orthogonal frequency-division multiplexing (MB-OFDM) UWB signal and all-optical frequency upconversion of UWB-OFDM subband. The impact of the nonlinearity of the optical link on the MB-OFDM signal is investigated through a simulation model of the complete UWB-over-fiber system. Results have shown enhanced performance of upconverted MB-OFDM subband compared to direct transmission due to optical noise reduction. First experimental results have confirmed simulation results.

Technologies for UWB-Over-Fiber

This paper investigates distribution and processing of ultrawideband signals for radio over fiber network. Architectures of single-mode and multimode systems are discussed to find a cost effective solution for UWB over fiber up and down-link systems

Signal and noise conversions in RF-modulated optical links

The power spectral density of the optical intensity in RF modulated optical links is investigated theoretically and experimentally in interferometric systems with a good agreement. The influence of the Henry factor /spl alpha/ of directly modulated distributed feedback laser diodes is shown on the conversion of phase noise into intensity noise for the first time.