An Ultrasensitive Gas Pressure Sensor Based on Single-Core Side-Hole Fiber With Optical Vernier Effect

An ultrasensitive optical fiber gas pressure sensor with the Optical Vernier effect (OVE) is proposed based on fusion splicing a piece of the Single-core and Side hole (SCSHF) fiber between the No-core fiber (NCF) and the hollow core fiber (HCF). The fabrication process only refers to the operation of fusion splicing, which is suitable for mass production. The theoretical sensing principles of the proposed sensor are explicitly elucidated in this paper. The sensor can be used as a probe in a narrow place because it works based on the reflected mode. The experimental results demonstrated that the sensor could detect the gas pressure change with a sensitivity of ∼183 nm/MPa in the range of 0∼100 kPa. Repeated experiments are also conducted to verify the sensor's excellent sensing repeatability and long-term stability. In addition, the sensor possesses a low-temperature cross-sensitivity of ∼2.4 kPa/°C. Thus, the proposed sensor is expected to leverage its practical functionalities in sensing areas requiring high sensitivity, a simple fabrication process, and long-term stability.