6.1 Sensing of physical properties

Optical sensors exploit diverse physical mechanisms and interpret them into measurable indicators, covering almost every monitoring need. Besides commercially available sensing elements, special constructions can be manufactured, further increasing the variety of indicators and data that can be captured. Integration with fiber-based data traffic networks is an advantage of these sensors, with respect to electrical ones, since they can be deployed in great distances, even for critical infrastructures.

Our group has dealt with manufacturing optical sensors, deploying them within existing infrastructure used for optical communications and providing user level services by collecting, interpreting and presenting the measurements from the optical sensor signals. Latest example is the manufacturing and deployment of critical infrastructure optical sensors in the metropolitan telecommunication optical ring of the Municipality of Edessa. Figure shows:

(a) Patch panel at access node of the city

(b) Vehicle detection, categorization and speed monitoring sensor installation

(c) Accelerometer sensor installation

(d) Rainfall measurement sensor installation.

 

Sensors manufactured include:

  • a high sensitivity FBG three-axes accelerometer,

  • a high resolution water level monitoring FBG sensor,

  • a high resolution rainfall monitoring FBG sensor, and

  • a traffic monitoring, vehicle classification and speed measuring FBG sensor.

All the above sensors were based on Finer Bragg Gratings. Data acquisition and analysis was performed by the use of an optical fast interrogator unit that could be located at different nodes within the network, as shown in the figure below.

 

Our group has also performed analytic studies regarding the power budget depending on the number of sensors, maximum optical fiber distances that could be used in the network, optimum location of interrogation unit etc. for various network installations. 

 

 

Related projects:

  • VASIS

 

Significant publications:

  • M. Bourmpos, A. Argyris, D. Syvridis, ‚ÄúSmart City Surveillance Through Low-Cost Fiber Sensors in Metropolitan Optical Networks", Fiber and Integrated Optics, Vol.33 Issue 3, 2014.