G. Maury

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

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.

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

Investigation on the Phase Noise and EVM of Digitally Modulated Millimeter Wave Signal in WDM Optical Heterodyning System

In this paper, theoretical model on phase noise in self-heterodyning optical system for mmW generation is proposed. Phase noise is impacted by optical path difference between both optical tones and laser source coherence time, but also by RF generators phase noise. Phase noise measurements of the mmW signal and RF sources have been realized to discuss the validity of the model. Based both on the theoretical approach and on the phase noise characterizations, an error vector magnitude (EVM) model is developed to quantify the impact of the optical self-heterodyning output phase noise on up-converted broadband digital signal (ECMA 387 standard).

Bidirectional millimeter-wave radio-over-fiber system based on photodiode mixing and optical heterodyning

We demonstrate a bidirectional millimeter-wave (mmW) radio-over-fiber system based on the use of a p-i-n photodiode (PD) biased in the nonlinear regime. Since frequency down-conversion and photodetection are carried out by a single photodiode, the base station (BS) architecture is simplified. Down-link transmission employs an optical heterodyning technique for mmW generation and remote local oscillator (LO) delivery to BSs. The up-link scheme uses the electrical port of the PD as an input for optoelectronic mixing with the remotely delivered LO. Up-link and down-link have been successfully demonstrated for 397 Mbps and 794 Mbps binary phase-shift keying complying with the 60 GHz ECMA 387 standard. Error vector magnitude measurements and theoretical analysis are discussed as regards optimal PD bias conditions. It is shown that PD can be used in this bidirectional system without any switching of the PD bias.

Conversions of the microwave subcarriers of digital signals in optical links

We present a technique for up and down-conversion of microwave (MW) subcarriers of digital signals based on the insertion of a passive all-optical device (unbalanced Mach-Zehnder interferometer) in a frequency modulated (FM) fiber-optic link. This technique has been successfully tested previously with CW signals. Here, simulations of digital transmission, spectral and BER measurements are presented. The technique uses a very low cost passive optical device that is also able to work with WDM and full duplex systems (1.3-1.5 /spl mu/m). The frequency range of operation is only limited by the direct modulation of the laser diode. BER measurements for BPSK format show low distortions caused by the system.

Multistandard Transmission Over Plastic Optical Fiber

This paper describes a multistandard fiber fed wireless system, which provides low-cost and enhanced performances regarding laser nonlinearity and RF transmitted power. Experimental results demonstrate that the proposed scheme provides not only optimized performances for low cost coming both from plastic optical fiber and vertical cavity surface emitting lasers (VCSELs), but also optimization of RF modulation power by complementary cumulative distribution function analysis and enhanced linear behavior by a whole new quasi-static approach of the VCSEL. With the help of those features, we successfully demonstrate minimization of error vector magnitude for simultaneous ultra-wideband multiband-orthogonal frequency division multiplexing and wireless local area network 802.11g optically transmitted signals and the possibility to use this system under conditions for symmetrical wireless communication.