Optical sensing in urban areas by deployed telecommunication fiber networks

The telecommunication fiber network already deployed in urban areas provides an added value to the optical asset itself, allowing a smart monitoring of our cities in a large scale. It is possible to use deployed PON infrastructures for structural vibration and local seismologic perturbations monitoring. On the other hand, surveillance of the embedded network and real-time safety diagnostic is also possible. The invited talk will present different experimental demonstrations to show the sensing performance by exploiting deployed fiber links, assessing the compatibility with the optical data telecom traffic at very high rate

Strain wave acquisition by a fiber optic coherent sensor for impact monitoring

A novel fiber optic sensing technology for high frequency dynamics detection is proposed in this paper, specifically tailored for structural health monitoring applications based on strain wave analysis, for both passive impact identification and active Lamb wave monitoring. The sensing solution relies on a fiber optic-based interferometric architecture associated to an innovative coherent detection scheme, which retrieves in a completely passive way the high-frequency phase information of the received optical signal. The sensing fiber can be arranged into different layouts, depending on the requirement of the specific application, in order to enhance the sensor sensitivity while still ensuring a limited gauge length if punctual measures are required. For active Lamb wave monitoring, this results in a sensing fiber arranged in multiple loops glued on an aluminum thin panel in order to increase the phase signal only in correspondence to the sensing points of interest. Instead, for passive impact identification, the required sensitivity is guaranteed by simply exploiting a longer gauge length glued to the structure. The fiber optic coherent (FOC) sensor is exploited to detect the strain waves emitted by a piezoelectric transducer placed on the aluminum panel or generated by an impulse hammer, respectively. The FOC sensor measurements have been compared with both a numerical model based on Finite Elements and traditional piezoelectric sensors, confirming a good agreement between experimental and simulated results for both active and passive impact monitoring scenarios

DEMONSTRATION OF STRUCTURAL VIBRATION SENSING OVER A DEPLOYED PON INFRASTRUCTURE

We demonstrate the possibility of using a deployed Passive Optical Network (PON) infrastructure for structural vibration monitoring for smart city applications and simultaneously downstream 10Gbit NRZ transmission. The impact of PON trunk fibre backscattering noise on sensing system performance is experimentally assessed

A PCR-colorimetric microwell plate hybridization assay for detection of Mycobacterium tuberculosis and M. avium from culture samples and Ziehl-Neelsen-positive smears

Differentiation between Mycobacterium tuberculosis and M. avium is essential for the treatment of mycobacterial infections. We have developed an easy and rapid detection assay for the diagnosis of mycobacterial diseases. This is a PCR-hybridization assay based on selective amplification of a 16S rRNA gene sequence using pan-Mycobacterium primers followed by hybridization of the amplification products to biotinylated M. tuberculosis and M. avium-specific probes. A total of 55 mycobacterial isolates were tested. For all isolates, results concordant with those of conventional identification methods were obtained. Moreover, we developed a method for extraction of DNA from Ziehl-Neelsen-positive smears which allows the recovery of intact target DNA in our PCR-hybridization assay. Our method was able to confirm all culture results for 59 Ziehl-Neelsen-positive smears from clinical specimens (35 sputum, 11 lymph node biopsy, 6 stool, 4 pus, 2 urine, and 1 pericardial fluid specimens). These data suggest that our PCR-hybridization assay, which is simple to perform and less expensive than commercial probe methods, may be suitable for the identification of M. tuberculosis and M. avium. It could become a valuable alternative approach for the diagnosis of mycobacterial infections when applied directly to DNA extracted from Ziehl-Neelsen-positive smears as well

Sensore a fibra ottica di tipo sinottico

Sensore a fibra ottica comprendente: una sorgente laser (10) che emette un primo raggio laser; un divisore ottico (11,55,60) che riceve detto primo raggio laser ed fornisce un secondo raggio laser ed un terzo raggio laser; una prima fibra ottica (20) che riceve detto secondo raggio laser; una seconda fibra ottica (24) che riceve detto terzo raggio laser; detta prima fibra ottica (20) ha la stessa lunghezza di detta seconda fibra ottica (24); detta prima fibra ottica (20) e detta seconda fibra ottica (24) sono affiancate tra loro; un mezzo trasmissivo (22, 35) associato a detta prima fibra ottica; un primo mezzo di riflessione (23,37,52,64) di detto secondo raggio laser applicato a detto mezzo trasmissivo (22, 35); un secondo mezzo di riflessione (25,52,53,64) di detto secondo raggio laser applicato a detta seconda fibra ottica (24); un primo mezzo ricevitore (13,50,55,60) posto tra detto divisore ottico (11,55,60) e detta prima fibra ottica (20), per ricevere detto secondo raggio laser riflesso (S) da detto primo mezzo di riflessione (23,37,52,64); un secondo mezzo ricevitore (16,51,55,60) posto tra detto divisore ottico (11,55,60) e detta seconda fibra ottica (24), per ricevere detto primo raggio laser riflesso (OL) da detto secondo mezzo di riflessione (25,52,53,64); un ricevitore coerente (30,53,55,60) che riceve detto secondo raggio laser riflesso (S) e detto primo raggio laser riflesso (OL) e fornisce in uscita segnali ottici in quadratura (I e Q); convertitori ottico/elettrici (31) che ricevono le uscite ottiche del ricevitore coerente (30,53,55,60) e producono segnali elettrici analogici che vengono convertiti in digitale (32) e forniti ad un processore di segnale digitale (33). (Fig.1

Performance analysis of communication links based on VCSEL and silicon photonics technology for high-capacity data-intensive scenario

To face the increased demand for bandwidth, cost-effectiveness and simplicity of future Ethernet data communications, a comparison between two different solutions based on directly-modulated VCSEL sources and Silicon Photonics technologies is carried out. Also by exploiting 4-PAM modulation, the transmission of 50-Gb/s and beyond capacity per channel is analyzed by means of BER performance. Applications for optical backplane, very short reach and in case of clientoptics networks and intra and inter massive data centers communications (up to 10 km) are taken into account. A comparative analysis based on the power consumption is also propose

Coherent Fiber-Optic Sensor for Ultra-Acoustic Crack Emissions

A coherent optical fiber sensor with adequate sensitivity for detecting the acoustic emission (AE) during the propagation of a crack in a ferrous material is presented. The proposed fiber optic sensor is successfully compared in terms of the SNR (Signal to Noise Ratio) and detectable AE energy levels to commercially available AE piezo-transducers sensors and is proven to be an effective and advantageous alternative for sensing and monitoring fatigue damage in structural applications