In this paper, we propose an improvement of the Chirped-Pulsed Frequency Modulation (C-PFM) FBGs reading
technique  as supported by new experimental results. The C-PFM technique, which was basically translated from its
counterpart in the field of radar signal analysis, exploits the intensity modulation of the probe signal (the light traveling
along the fiber in our case) by means of a sinusoid with a linearly variable frequency and a train of pulses, to improve the
spatial resolution of the acquisition system. The response discrimination of the FBG sensors is achieved thanks to an infiber
linear filter and a novel adaptive numerical filtering as it will be better explained in the following. Using a peculiar
time window shaping (Blackman) of the light pulse we intended to improve the cross-talk features of the reading
In this work we present the first experimental results of a new multidisciplinary activity concerning active structural
control. Specifically, exploiting Fiber Bragg Grating (FBG) sensors and Piezoelectric actuators, an adaptive control
approach was adopted to damp the vibrations of a cantilever beam. The strain sensor used for the structural vibration
detection is a Bragg Grating written on a single-mode optical fiber for telecom applications. The reading technique used
to detect the variations in the &lgr;B of the grating due to the local strain variations, exploits a narrow band laser tuned to the
mean wavelength of the grating reflectance spectrum roll-off, as it will be better explained in the following. The results
obtained so far demonstrate how the combined application of novel strain sensors and a clever control approach can
provide a benefit in terms of bandwidth, damping speed and reduced design effort.
In this work we aim to realize a step-by-step electro-optical probe which exploits the linear (Pockels) electro-optic effect
to survey the electromagnetic field on the surface of RF integrated circuits. This probe measures the variation of light
polarization induced by a lithium niobate crystal immersed in the electric field provided by the DUT. The measurements
will demonstrate the main features of this system which can be summarized in non-invasiveness, wide bandwidth,
linearity and small spatial resolution.
The LiNbO3 crystals have been developed by SELEX Sistemi Integrati S.p.A. Roma, and the whole research activity has
been carried out under the sponsorship of the CRdC Nuove Tecnologie per le Attivita Produttive, the Campania Region
Centre of Competence on New Technologies.
This contribution gives a description of the Sardinia Radio Telescope (SRT), a new general purpose, fully steerable antenna proposed by the Institute of Radio Astronomy (IRA) of the National Institute for Astrophysics. The radio telescope is under construction near Cagliari (Sardinia) and it will join the two existing antennas of Medicina (Bologna) and Noto (Siracusa) both operated by the IRA. With its large antenna size (64m diameter) and its active surface, SRT, capable of operations up to about 100GHz, will contribute significantly to VLBI networks and will represent a powerful single-dish radio telescope for many science fields. The radio telescope
has a Gregorian optical configuration with a supplementary beam-waveguide (BWG), which provides additional focal points. The Gregorian surfaces are shaped to minimize the spill-over and the standing wave between secondary mirror and feed. After the start of the contract for the radio telescope structural and mechanical fabrication in 2003, in the present year the foundation construction will be completed. The schedule foresees the radio telescope inauguration in late 2006.