Pascal Morel

Experimental and Simulation Analysis of the Third-Order Input Interception Point in an All-Optical RF Mixer Based on a Semiconductor Optical Amplifier

We present an experimental and computing analysis of the nonlinear distortions of an all-optical radiofrequency mixer based on cross-gain modulation (XGM) in a semiconductor optical amplifier (SOA). Such an all-optical mixer is well suited for radio-over-fiber (RoF) applications. The simulation results are based on a SOA model developed under ADS™ software and are compared to experimental results in various cases. The good correlation between experimental and simulation results permits to demonstrate the ability of our SOA model to study mixing phenomenon by using a Harmonic Balance (HB) simulation method. Optical third-order input intercept point (IIP3) and its electrical equivalent are determined experimentally and by simulation with a good concordance. An optical IIP3 of -5 dBm and a spurious free dynamic range (SFDR) of 85.7 dB/Hz are obtained for a radiofrequency signal at 1 GHz. Moreover, simulations show that the IIP3 increases, all other parameters being equal, when the SOA active zone is shortened.

Enhanced performance of semiconductor optical amplifier at high direct modulation speed with birefringent fiber loop

We employ a birefringent fiber loop (BFL) for enhancing the performance of a semiconductor optical amplifier (SOA) which is directly modulated. By properly exploiting the BFL comb-like spectral response, we show that the SOA can be directly modulated at a data rate which is more than five times faster than that enabled by the SOA electrical bandwidth. The experimental results, which include chirp measurements, demonstrate the significant improvements achieved in the performance of the directly modulated SOA with the help of the BFL.

Towards energy-proportional clouds partially powered by renewable energy

With the emergence of the Future Internet and the dawning of new IT models such as cloud computing, the usage of data centers (DC), and consequently their power consumption, increase dramatically. Besides the ecological impact, the energy consumption is a predominant criterion for DC providers since it determines the daily cost of their infrastructure. As a consequence, power management becomes one of the main challenges for DC infrastructures and more generally for large-scale-distributed systems. In this paper, we present the EpoCloud prototype, from hardware to middleware layers. This prototype aims at optimizing the energy consumption of mono-site Cloud DCs connected to the regular electrical grid and to renewable-energy sources.

The EPOC project: Energy proportional and opportunistic computing system

With the emergence of the Future Internet and the dawning of new IT models such as cloud computing, the usage of data centers (DC), and consequently their power consumption, increase dramatically. Besides the ecological impact, the energy consumption is a predominant criteria for DC providers since it determines the daily cost of their infrastructure. As a consequence, power management becomes one of the main challenges for DC infrastructures and more generally for large-scale distributed systems. In this paper, we present the EPOC project which focuses on optimizing the energy consumption of mono-site DCs connected to the regular electrical grid and to renewable energy sources.

Dimensioning of 112G optical-packet- switching-based interconnects for energy-efficient data centers

We present the dimensioning of an optical packet switching network for energy-efficient intradata- center connections. Our approach relies on one or two interconnection stages derived from the timewavelength- interleaved network concept and relying on fast wavelength-tunable lasers.We compare several options by numerical simulation to increase the bit rate of the intra-data-center links up to 112 Gbit/s. The analysis focuses on pulse-amplitude modulation (4 and 8 PAM), where a pre-distortion mechanism is introduced and three types of optical receivers are taken into account. Possible dispersion of device characteristics is taken into account. The single-stage system should enable us to connect 48 servers using 8 PAM and semiconductor-optical amplifier (SOA)-PIN in conjunction with a 62.5 GHz grid. In the two-stage configuration, this number increases up to 1488.

A Joint Linearization/Companding Approach for Improving a CO-OFDM Transmitter

The joint use of peak-to-average power ratio (PAPR) reduction and linearization via digital predistortion is investigated in this letter, with the view to improve the performances of coherent optical OFDM systems employing a semiconductor optical amplifier. The PAPR reduction is performed via Wangs nonlinear companding transform, which has been recently pointed out as a pertinent choice for optical communications, and a filter lookup table scheme is considered for linearizing the transmitter. Experimental results prove the effectiveness of the proposed scheme, as a lower error vector magnitude is achieved with respect to system implementations using only the PAPR reduction or linearization.

A semi-phenomenological model for the material gain of broadband MQW-SOAs

We propose a semi-phenomenological model to calculate the material gain of multiple quantum well broadband Semiconductor Optical Amplifier (SOA). We show that this proposed model permits to fit well the experimental results of a broadband SOA gain and noise figure over a range of 100nm.

Improving SOA direct modulation capability with optical filtering

Semiconductor optical amplifiers (SOAs) have been receiving intense interest for use as external modulators in a variety of fundamental and advanced applications. However the employment of these modules for the target purpose is hindered by their limited modulation bandwidth. Motivated by this fact, in this invited paper we review the main outcome of our recent research on enabling the direct modulation of SOAs with improved performance at enhanced data speeds. In this context we present experimental and theoretical results that we have obtained by exploiting different types and combinations of optical filters. These filters include the birefringent fiber loop (BFL), either alone, in cascade with another BFL or assisted by an optical bandpass filter (OBPF), and a passive single microring resonator (MRR). To this end we demonstrate the capability of the schemes to efficiently overcome the pattern-dependent response of the directly modulated SOA and enhance the quality characteristics of the encoded signal.

Extended Passive Optical Pod Interconnect for small mono-site data centers

We compare two all-optical data-center interconnects, POPI (Passive Optical Pod Interconnect) and POITR (Passive Optical Interconnect at Top of the Rack). We show that POPI is better in terms of link power budget and thus more suited to an increase of modulation format complexity. An extension of this solution is proposed by the use C and L transmission bands, which enables doubling the number of connected entities.

Test Device for Blood Transfusion Safety - How Acoustics Can Help Preventing Any Red Cells Incompatibility

During red cells concentrates transfusion , red cells incompatibilities still occur despite t he laboratory controls based on immuno-hematologic techniques. Red cells incompatibilities appear when patient’s antibodies bind to red cells to be transfused. Up t o now, all pre-transfusion testing are addressed us ing techniques based on immunology. This is time consum ing, expensive and some incompatibility situations cannot be addressed at the patient’s bedside. In th is position paper, we propose a completely novel paradigm. Our hypothesis is that red blood cells se nsitized by the patient’s antibodies see their defo rmability greatly reduced. This induces changes of the rheolo gical properties of the “red cells concentrate /pat ient’s blood” mixture. Studies described in this position paper aim at characterizing these modifications by measuring the characteristics of acoustic waves pro pagating in the mixture and to produce a mobile and automated acousto-micro-fluidic device which would a low detecting any incompatibility at the patient’ s