Sensitivity-enhanced fiber optic temperature sensor with strain response suppression

A temperature sensor based on a multimode–singlemode–multimode (MSM) fiber structure has been proposed and experimentally demonstrated. By utilizing the interference between fiber core and cladding modes, temperature measurement is exploited by monitoring the selected resonant dips shift of the transmission spectrum. A high temperature sensitivity of 50.65 pm/°C is achieved at a certain resonant dip, accompanied by a suppressed strain sensitivity of only 0.587 pm/με. The sensor reveals the advantages of easy fabrication and interrogation, low cost and small axial strain response.

• We demonstrate a compact all fiber interferometer for temperature sensing.
• The interference characteristic is theoretically investigated.
• High temperature with suppressed axial-strain response has been achieved.
• The sensor has the intrinsic ability to overcome the strain-sensitive effect.
• The sensor can be used in the field of high-precision temperature sensing.