Abstract
A microfibre device integrating a microfibre knot resonator in a Sagnac loop reflector is proposed for refractive index and temperature sensing. The reflective configuration of this optical structure offers the advantages of simple fabrication and ease of sensing. To achieve a balance between responsiveness and robustness, the entire microfibre structure is embedded in low index Teflon, except for the 0.5–2 mm diameter microfibre knot resonator sensing region. The proposed sensor has exhibited a linear spectral response with temperature and refractive index. A small change in free spectral range is observed when the microfibre device experiences a large refractive index change in the surrounding medium. The change is found to be in agreement with calculated results based on dispersion relationships.
Highlights
IntroductionThere has been an increasing interest in the fabrication of miniaturized optical devices using microfibres due to the advantages of strong light confinement within the waveguide, great
There has been an increasing interest in the fabrication of miniaturized optical devices using microfibres due to the advantages of strong light confinement within the waveguide, greatSensors 2012, 12 flexibility in bending and twisting, high sensitivity to ambient conditions, simple fabrication and facile integration with optical fibre systems
The results have indicated that the sensor is capable of maintaining a consistent linear variation in spectral shift with both refractive index (RI) and temperature change
Summary
There has been an increasing interest in the fabrication of miniaturized optical devices using microfibres due to the advantages of strong light confinement within the waveguide, great. The light confined in the microfibre creates a large evanescent field in the surroundings which enables a strong interaction between the light and the ambient medium This property has been exploited using different approaches for refractive index (RI) sensing [1,2] with the sensitivity being enhanced by adopting thinner microfibres to achieve larger evanescent fields [3]. Additional methods of refractive index sensing using photonic crystal fibres and optofluidics microchannels offering similar or better sensitivity have been reported [4,5] These complex structures are not as produced, which translates into longer design-fabrication cycles. Another advantage of the large evanescent field of a microfiber is that it enables interaction of light between microfibres, making manipulation of light and the corresponding optical functions possible. In relation with the effective index of the microfibre, a small variation in the free spectral range (FSR) was observed when the microfibre device experienced a large RI change in the surrounding medium, which is explained through dispersion relations
Sign-in/Register to view highlights & summary Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a callDisclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.
