We report a linear response optical refractive index (RI) sensor, which is fabricated based on a micro-channel created within a Fabry Perot (F-P) cavity by chemical etching assisted by femtosecond laser inscription. The experimental results show the F-P resonance peak has a linear response with the RI of medium and the measuring sensitivity is proportion to the length of micro-channel. The sensor with 5 μm -long micro-channel exhibited an RI sensitivity of 1.15nm/RIU and this sensitivity increased to 9.08nm/RIU when widening the micro-channel to 35μm. Furthermore, such micro-channel FP sensors show a much broader RI sensing dynamic range (from 1.3 to 1.7) than other reported optical fiber sensors.

Date Published: 25 April 2012
PDF: 7 pages
Proc. SPIE 8426, Microstructured and Specialty Optical Fibres, 842609 (25 April 2012); doi: 10.1117/12.921410

Published in SPIE Proceedings Vol. 8426:
Microstructured and Specialty Optical Fibres
Kyriacos Kalli; Alexis Mendez, Editor(s)