Global temperature measurements of aluminum alloy specimens with embedded optical fibers

Several types of sensors based on optical fiber technology are available today. They can be classified into two wide categories: sensors for local and global measurements. The first ones are more expensive since they imply further processing of the optical fiber while the second one uses it directly as provided by the manufacturer. The disadvantage is that only the value of the physical quantities integrated over the fiber length can be retrieved. This is not a limitation for the present research because the main purpose of this work is to show that the process of embedding into metallic materials does not damage the optical fiber properties thus opening the way for further studies on other fiber optic sensors such as the Fiber Bragg Gratings. In the paper will be presented two different technologies for integrating the optical fibers into Aluminum alloys for aerospace use. One, tested only qualitatively in an earlier work, have been used here to build specimens with embedded optical fiber to be used as one arm of a Michelson interferometer. The results, relevant to temperature measurement. are quite satisfactory. The second one, still under development but more adequate to actual space and mechanical applications will be briefly considered.