Simultaneous measurement of bending and temperature based etched PMFBG FP filter

•The optical fiber sensor is based on etched PMFBG Fabry-Perot filter.•Two resonance wavelengths show different response to bending and temperature.•The simultaneous detection of bending and temperature can be realized. An etched polarization maintaining fiber Bragg grating (PMFBG) Fabry-Perot filter for simultaneous measurement of bending and temperature is proposed and experimentally demonstrated. A 4 mm region between two PMFBGs is etched. As bending or temperature is applied to the sensor, the resonance wavelength of the two orthogonal polarization modes shift. Meanwhile, the wavelength interval between the resonance wavelength of two orthogonal polarization modes changes proportionally to the temperature, while it remains the same as the bend angle increases. Due to different responses of the filter to bending and temperature change, the device can be used for the simultaneous measurement of bending and temperature.