A fiber optic refractive index sensor based on Fabry-Perot interferometer formed by two Chirped Fiber Bragg Gratings on a seven-core fiber is successfully demonstrated. A small part of the fiber cladding is etched to expose the outer 6 cores to the ambient environment. While optical modes supported by the outer 6-cores are affected by both temperature and refractive index changes of the surrounding liquid, the optical mode in the central core is affected by the temperature changes only. Because only a small part of the cladding is removed, the sensor maintains excellent mechanical strength and stability.
A four-core optical fiber is used to investigate one-dimensional heat transfer measurements. Heat pulses from a Nd:YAG laser of 600 ms duration with a repetition rate of the order of 10 s are delivered onto one of the fiber cores. This results in an optical path length difference between the guiding cores due to the change in the refractive index and physical length of the targeted fiber core. As a result of this process, a phase shift of 1.30 rad is measured with a digital camera for 140 mW pulses in reflection scheme. The heat diffusion length in the selected fiber core is determined to be 2.8 mm, which contains 33.2 kJ/m2s heat, causing a temperature rise of 4.30 K.
Access to the requested content is limited to institutions that have purchased or subscribe to SPIE eBooks.
You are receiving this notice because your organization may not have SPIE eBooks access.*
*Shibboleth/Open Athens users─please
sign in
to access your institution's subscriptions.
To obtain this item, you may purchase the complete book in print or electronic format on
SPIE.org.
INSTITUTIONAL Select your institution to access the SPIE Digital Library.
PERSONAL Sign in with your SPIE account to access your personal subscriptions or to use specific features such as save to my library, sign up for alerts, save searches, etc.