Search

• A fiber H 2 sensor based on a hybrid FPI and MI probe with PDMS and Pd-WO 3 is reported. • MI and FPI are cascaded to form a vernier spectrum. • The sensor has superiorities of excellent repeatability, rapid response, high sensitivity, and compact structure. • The sensor has impressive potential in the detection of H 2 in narrow places. A hydrogen (H 2) sensor based on hybrid Fabry-Perot interference (FPI) and Michelson interference (MI) with Vernier effect is demonstrated. The optical probe is manufactured by fusing a multimode fiber (MMF) and a double-side hole fiber (DSHF) between a single-mode fiber (SMF) and a hollow core fiber (HCF) filled with polydimethylsiloxane (PDMS) at the end to form a cascaded FP and MI, which can generate a vernier envelope. by fusing a multimode fiber (MMF) and a double-side hole fiber (DSHF) between a single-mode fiber (SMF) and a hollow core fiber (HCF) filled with PDMS at the end. To accomplish H 2 sensing, palladium-tungstic oxide (Pd-WO 3) powder is attached to the exterior surface of PDMS, which will cause an exothermic redox reaction with H 2. The released heat will lead to the volume expansion of PDMS with remarkable thermal response characteristics, and finally cause the movement of the vernier-like spectral envelope with the variation of H 2 concentration. The sensitivity of the proposed sensor is 2.2 nm/% in the range of 0 %–1% through the H 2 measurement experiment. For H 2 with a concentration of 1 %, it has the response time of 28 s and shows good reversibility in the cyclic experiment. In addition, the sensitivity of temperature and relative humidity (RH) is 0.21 nm/°C and 0.0014 nm/%RH, respectively. The proposed sensor adopts a reflective probe, which is compact in structure and small in volume, and shows fast response and excellent repeatability. It has great advantages in H 2 measurement in narrow spaces and long distances. [ABSTRACT FROM AUTHOR]

• Optic fiber coupled surface plasmon resonance senso is proposed for hydrogen sensing. • The optical double-path SPR design is simple, stable and takes advantage of intensity interrogation. • An Ag/TiO 2 film deposited on the prism substrate can be replaced for various sensing applications. We propose and demonstrate the fiber optic Surface Plasmon Resonance (SPR) for hydrogen sensing based on Ag/TiO 2 at the telecommunications wavelength of 1550 nm. The sensor using TiO 2 as a sensitive layer for hydrogen detection consists of a multilayer film of 45 nm Ag/110 nm TiO 2 deposited on the coupling prism substrate. An intensity interrogation SPR with Kretschmann configuration is designed, where SPR phenomenon will occur at the interface of the Ag/TiO 2 film, and the hydrogen concentration will be detected by measuring the change in the reflected intensity. The sensitivity of the sensor is optimal at an Ag/TiO 2 thickness. Simulation and experimental results demonstrate that the fiber-optic SPR sensor developed provides hydrogen sensing and has a high sensitivity to a hydrogen concentration ranging between 14.7% and 25% Hydrogen in Air, reaching 523nW/%. [ABSTRACT FROM AUTHOR]