Optical refractometer based on a birefringent Bragg grating written in an H-shaped fiber

An optical refractometer based on a birefringent (Hi-Bi) fiber Bragg grating (FBG) written in a new H-shaped fiber structure is proposed. This structure is formed by opening the two holes of a side-hole fiber using chemical etching. When the Hi-Bi FBG is immersed in different liquids, different responses of the slow and fast wavelengths are obtained. The refractometer is also capable of simultaneous measurement of refractive index and temperature. (c) 2008 Optical Society of America OCIS codes: 060.2310, 060.3735, 060.2370.