Heng, S.Nguyen, M.C.Kostecki, R.Monro, T.Abell, A.Baldini, F.Homola, J.Lieberman, R.A.2013-09-182013-09-182013Optical Sensors 2013 / F. Baldini, J. Homola, R. A. Lieberman (eds.): Paper 87740397808194957610277-786X1996-756Xhttp://hdl.handle.net/2440/80076Femtosecond laser written Bragg gratings have been written in exposed-core microstructured optical fibers with core diameters ranging from 2.7 μm to 12.5 μm and can be spliced to conventional single mode fiber. Writing a Bragg grating on an open core fiber allows for real-time refractive index based sensing, with a view to multiplexed biosensing. Smaller core fibers are shown both experimentally and theoretically to provide a higher sensitivity. A 7.5 μm core diameter fiber is shown to provide a good compromise between sensitivity and practicality and was used for monitoring the deposition of polyelectrolyte layers, an important first step in developing a biosensor.en© 2013 SPIEConference paper003000044810.1117/12.20165100003233262000022-s2.0-8488073145764454Kostecki, R. [0000-0001-5822-8401]Abell, A. [0000-0002-0604-2629]