169,942 research outputs found
Resonant optical gyro: Monolithic vs. hybrid integration
No full textSince several decades, angular velocity sensors are considered crucial devices in a wide range of vehicles such as military and civil airplanes, military ships, submarines, satellites, space launchers, and long-range ballistic missiles. The interest towards miniaturized gyroscopes for aerospace and defense industry has given rise to an increasing research effort aiming at the scaling of optical gyros through integrated optical technologies. In particular, the resonant optical gyro (ROG) has been identified as the ideal candidate for a new generation photonic angular velocity sensor. Two technological approaches are available to implement the ROGs, i.e., the hybrid integration of optoelectronic components manufactured on different substrates or the monolithic integration of all components on a single chip. The two options are critically discussed and compared in this paper with a special attention on integrated gyroscopes (gyro-on-a-chip, GoC) in silica on silicon and indium phosphide that have been recently theoretically and experimentally studied, demonstrating promising results
Modelling and design of an electrically-pumped DFB laser based on an erbium-doped silicon-rich silicon oxide layer embedded in a slot waveguide
No full textThe development of a high-performance DFB laser compatible with the CMOS technology is essential for the future development of silicon photonics. In this paper the preliminary results on modelling and design of a distributed feedback silicon laser are reported. The gain medium, which is a layer of erbium doped silicon-rich silicon oxide, is embedded in a horizontal slot waveguide. The designed device includes a grating with 140 periods and a quarter-wave phase shift at the grating middle. The threshold gain coefficient of the laser is 0.4 cm(-1) and the emission wavelength is very close to 1.55 mu m
Contact-Less Body Temperature Monitoring by Infrared Camera: Accuracy Preliminary Assessment
No full textAccurate and non-invasive measurement of body temperature is crucial for early disease diagnosis, patient condition monitoring, and infection control in hospital environments. In this paper, we preliminary assess the accuracy of an embedded electronic system based on the MLX90640 thermal camera, with the final goal of integrating it in a hospital robot provided of an advanced and automated monitoring system. The MLX90640 thermal camera, combined with a specially developed algorithm, accurately measured patients' body temperature in a non-invasive and continuous manner, with a maximum absolute error equal to 0.2 °C. The preliminary results suggest that integrating the MLX90640 thermal camera into a device for vital signs monitoring represents a promising solution for efficient and reliable body temperature monitoring in hospital departments. The application of this technology could enhance the quality of healthcare, enabling timely interventions for patients
Numerical and experimental investigation of an optical high-Q spiral resonator gyroscope
No full textAn integrated optical gyroscope based on a passive silica-on-silicon resonator with a footprint of about 20 cm(2) is reported in this paper. The optical characterization of the cavity has been carried out and the main experimental results are discussed. We derive the sensor performance in terms of minimum detectable angular velocity (or resolution) delta Omega, underlining also the impact of the insertion loss in the silica-on-silicon device. Finally, we describe some technical approaches for improving the resolution
Variabilità dell'olio essenziale diHelichrysum italicum(Roth) G. Don
No full textPer lo studio dell'olio essenziale diHelichrysum italicum, sono state prese in considerazione varie
stazioni diE. italicum(Roth) G. Don subsp.microphyllum(Willd.) Nyman vegetante
allo stato spontaneo sia nel Nord che nel Sud della Sardegna. Le analisi sono state
condotte via Gas-massa e ci hanno permesso di identificare 69 costituenti per un totale
compreso tra il 92.9% ed il 99.9% dei costituenti totali
Optoelectronic gyroscope based on a high-Q InGaAsP/InP ring resonator: Preliminary results of the system test
No full textIn the last few years the interest towards miniaturized gyroscopes for aerospace & defence applications is quickly growing. In this context the development of a photonic gyroscope-on-chip based on the InP technology, which is increasing its maturity level, seems to be very promising. After the design, fabrication, and optical characterization of an InP gyro-oriented ring resonator with a performance improving the state-of-the-art of one order of magnitude, the development activity is now focused on the sensor readout electronics and the system test. Recently a test bench including the InP cavity, a two-channels lock-in amplifier, a custom electronic board, and other optical and optoelectronic off-the-shelf components has been set up. Some preliminary results of the system test are reported in this paper. A carrier suppression which is appropriate for the backscattering noise mitigation has been achieved and the sensor functionality has been experimentally proved
Design of a lithium niobate 2D E-field photonic probe
No full textDesign of an optoelectronic sensor allowing the estimation of two E-field components is illustrated in this paper. The lithium niobate device, which includes two Mach-Zehnder modulators, an integrated beam splitter, and a segmented electrode antenna, has a minimum detectable field < 1 mV/m and a bandwidth of about 8 GHz.
The sensor can be used as basic building block of an array of identical devices to survey both amplitude and phase of the field. The probe would facilitate the antenna diagnosis with the aim of improving its effectiveness. The array applications for near-field and very near-field characterization of radiating systems are briefly discussed
Design of a polymer photonic crystal membrane cavity for channel drop filtering in coarse wavelength division multiplexing networks
No full textA low-cost polymer integrated optical filter for coarse wavelength division multiplexing systems has been modelled, designed and optimized. The device, which can be manufactured by nanoimprinting lithography, is a Fabry-Perot cavity working at 1551 nm and consisting of a membrane-type slab photonic crystal in which a hole row perpendicular to the propagation direction is removed to form the two reflectors. The dependence of the resonator performance on the key geometrical parameters, i.e. the hole radius and the defect length, has been investigated by the finite element method. A good agreement between the requirements due to the specific application and the device performance has been obtained. The optimized filter, with a footprint of 43.7 μm2, has a Q-factor of 115 and a resonance transmission > 50
Multiple ring resonators in optical gyroscopes
No full textIn recent years there has been an increasing research interest aimed at the development of innovative integrated optic gyroscopes. Some authors have investigated coupled-resonator waveguiding structures formed by microrings mainly for their capability of manipulating light velocity, proposing also their application in phasesensitive optic gyroscopes. In this work we analyze the main performance parameters of an integrated optic gyroscope consisting of a three coupled ring resonator structure having different radii and coupling coefficients. The main result is the enhancement of the scale factor of the multi-ring-based gyroscope, without increasing the overall footprint, with respect to a conventional single ring resonator gyro. The final sensitivity of the gyroscope is also evaluated and compared with the conventional integrated optic gyroscope configuration
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