Temperature-insensitive Mach-Zehnder interferometric strain sensor based on concatenating two waist-enlarged fiber tapers

A novel temperature-insensitive strain sensor,based on an in-line Mach-Zehnder interferometer,is fabricated by concatenating two waist-enlarged fiber tapers separated by a short piece of photonic crystal fiber. The interference spectrum of the proposed sensor is analyzed in detail.Experimental results demonstrate that this sensor has a strain sensitivity of.3.02 pm/μεand maintains the temperature insensitivity feature. The proposed sensor has great potential in diverse sensing applications due to its advantages,such as its compact size,low cost,and simple fabrication process.     

In-line Fabry-Perot refractive index sensor based on microcavity

An in-line Fabry-Perot （FP） refractive index （RI） sensor based on an intrinsic FP cavity and fabricated by the etching and fusion splicing method is proposed. The experimental results demonstrate that the sensor possesses a high resolution of 1508 nm/RIU for the measurement of acetylene gas RI. The temperature- response measurement shows that the sensor is insensitive to room temperature variations. The FP RI sensor is suitable for applications in biosensing and environmental monitoring because of its high sensitivity and structural simplicity, thereby making it suitable for low-cost mass production.