Industrialization of advanced optical technologies for environmental monitoring

Abstract

In this work, an innovative fully integrated monitoring infrastructure based on optical fibre sensors was developed and implemented. In the framework of the research project named PROTEU [Tecnologias Avançadas para a Monitorização de Sistemas Estuarinos e Costeiros (PDCTM/P/MAR/15275/1999)], an 11 km optical fibre cable with Bragg sensors each 500 m was installed from the lagoon mouth to Vouga river, along the bed of the Espinheiro channel, allowing the real-time measurement of water temperature at each sensor location. The results of this project are currently feeding several studies concerning Ria de Aveiro and the surrounding area and are crucial for a continuous assessment and management of the environmental conditions. Meanwhile, a fibre optic sensing system for simultaneous measurement of temperature and salinity based on fibre Bragg grating (FBG) technology was also developed. In the following sections, a complete description of the fabrication process, as well as theoretical and experimental results regarding this particular sensing system, are addressed. Earlier in situ local measurements, as well as the latest remote monitoring and data processing scheme, are described. The developed technology is now being exploited by FiberSensing, an INESC Porto spin-off company devoted to the development of optical fibre Bragg grating-based sensor systems for advanced monitoring applications. The main markets of the company are the ones of structural health monitoring in civil and geotechnical engineering, energy production and distribution, and environment.