A Slot Shape Microstructured Optical Fiber for High Sensitivity Pressure Sensing

High pressure sensing is vital in industries, where pressures are precisely monitored. Herein, a slot shape microstructured optical fiber was designed and fabricated to achieve high sensitivity for pressure sensing in large measurement range. The cross-section of the optical fiber is a slot-like flattened circle. The core in the fiber center was compressed by two arms connected to the cladding shell when external pressure was applied, inducing changes in birefringence, and pressure sensing was achieved from the strong interference of the two modes in orthogonal polarization states. The pressure sensitivity reached 166.37 nm/MPa with a pressure range from 0 to 1 MPa. The sensitivity slightly decreased with the increase of pressure. Compensation of temperature influence was realized by inscribing a Bragg grating on the fiber core. The developed slotted optical fiber sensor has great prospects for high pressure measurement in various application scenarios.