Simultaneous Measurement of Refractive Index and Temperature Based on a Long-Period Grating Inscribed on a Polarization-Maintaining Fiber

摘要

Simultaneous measurement of refractive index (RI) and temperature by using a long-period fiber grating inscribed on a polarization-maintaining fiber (PM-LPG) was demonstrated. Two adjacent resonant dips (fast-axis and slow-axis resonant dips) which corresponding to the two principle polarizations along the fast and slow axes of the PM-LPG were shift with the external RI and temperature variation. Based on a PM-LPG, the sensitivities of each resonant dip for RI and temperature were different in magnitude and sign. This PM-LPG based sensor has a capability of simultaneously measurement external refractive index and temperature. The maximum error for refractive index and temperature were 0.001 RIU and 0.1℃ over range of 1.35 to 1.47 and 20 to 70℃, respectively.