Design of a Sensor Based on Plastic Optical Fibre (POF) to Measure Fluid Flow and Turbidity

Although many optical fibre applications are based on their capacity to transmit optical signals with low losses, it can also be desirable for the optical fibre to be strongly affected by a certain physical parameter in the environment. In this way, it can be used as a sensor for this parameter. There are many strong arguments for the use of POFs as sensors. In addition to being easy to handle and low cost, they demonstrate advantages common to all multimode optical fibres. These specifically include flexibility, small size, good electromagnetic compatibility behaviour, and in general, the possibility of measuring any phenomenon without physically interacting with it. In this paper, a sensor based on POF is designed and analysed with the aim of measuring the volume and turbidity of a low viscosity fluid, in this case water, as it passes through a pipe. A comparative study with a commercial sensor is provided to validate the proven flow measurement. Likewise, turbidity is measured using different colour dyes. Finally, this paper will present the most significant results and conclusions from all the tests which are carried out.

A Self-Referencing Intensity Based Polymer Optical Fiber Sensor for Liquid Detection

A novel self-referencing fiber optic intensity sensor based on bending losses of a partially polished polymer optical fiber (POF) coupler is presented. The coupling ratio (K) depends on the external liquid in which the sensor is immersed. It is possible to distinguish between different liquids and to detect their presence. Experimental results for the most usual liquids found in industry, like water and oil, are given. K value increases up to 10% from the nominal value depending on the liquid. Sensor temperature dependence has also been studied for a range from 25 degrees C (environmental condition) to 50 degrees C. Any sector requiring liquid level measurements in flammable atmospheres can benefit from this intrinsically safe technology.

Seabed Sensor Technology, Savannah, Georgia, February 1-3, 2006: workshop proceedings

Future coastal management practices require that a holistic, ecosystem management approach be adopted. Coastal ecosystems, however, present a variety of specific and unique challenges relative to open ocean systems. In particular, interactions with the seabed significantly influence the coastal ecosystem. Observing technologies must be developed and employed to incorporate seafloor interactions, processes and habitat diversity into research and management activities. An ACT Workshop on Seabed Sensor Technology was held February 1-3, 2006 in Savannah, Georgia, to summarize the current state of sensor technologies applicable to examining and monitoring the coastal seabed, including the near-bed benthic boundary layer and surface sediment layer. Workshop participants were specifically charged to identify current sensors in use, recommend improvements to these systems and to identify areas for future development and activities that would advance the use of sensor technology in the observation, monitoring and management of the coastal benthic environment. (pdf contains 23 pages)