Suspended Ring-Core Photonic Crystal Fiber Gas Sensor With High Sensitivity and Fast Response

• Main Authors: Sahar Hosseinzadeh Kassani, Reza Khazaeinezhad, Yongmin Jung, Jens Kobelke, Kyunghwan Oh
• Format: Article
• Language: English
• Published: IEEE 2015-01-01
• Series: IEEE Photonics Journal
• Subjects: Sensors; photonic crystal fiber; fiber optics systems.
• Online Access: https://ieeexplore.ieee.org/document/7021904/

We demonstrate the design and fabrication of an in-line evanescent field gas sensor based on a novel suspended ring-core photonic crystal fiber (PCF) to further overcome limitations in sensing capability. The suspended ring-core PCF is made by the stack-and-draw technique with a large central capillary of ~60 μm and adapted small capillaries in a larger cladding tube. Sensing capabilities of two variations of the proposed suspended ring-core PCFs were investigated experimentally by detecting absorption lines of acetylene gas. The sensitivity of the two PCF structures was also numerically analyzed using a full-vectorial finite-element method. The dynamic response of the sensors was quantified in detail. The results demonstrated significant improvement in both sensitivity and response time of the suspended ring-core PCF as this special PCF can provide larger gas diffusion and higher overlap between the sensing species and the guided light than either a Ge-doped ring defect PCF or a conventional index-guided PCF.