RESUMO
In this Letter, an in-fiber dual-channel surface plasmon resonance (SPR) sensor is reported that uses polydimethylsiloxane (PDMS)-filled C-type microstructured optical fiber (COF). The COF is made of HF-acid-etched single-sided hole optical fiber (SSHF), and its inner and outer sides are coated with gold film to stimulate SPR. The inner channel is filled with PDMS and acts as the temperature measurement channel, and the outer channel is directly in contact with the salt solution and acts as the salinity measurement channel. Experiments show that the sensor is qualified to detect salinity and temperature simultaneously, and it exhibits a salinity sensitivity of 0.296â nm/ in the salinity range of 0-153.32 and a high temperature sensitivity of -2.4â nm/°C in the temperature range of 22-44°C. Furthermore, the sensor also enjoys good hysteresis, repeatability, and reversibility in salinity detection. In a word, the high sensitivity, simple preparation, and good integration of the proposed sensor endow it with the potential for deep-sea exploration.
RESUMO
In this paper, a highly sensitive temperature compensated fiber optic magnetic field sensor by Sagnac and Mach-Zehnder combination interference (SMZI) is proposed and verified. The sensing structure relies on microstructured exposed core fiber (ECF) filled with ethanol and magnetic fluid (MF). The refractive index of MF and ethanol is affected by the magnetic field and temperature (MFT). SMZI is based on the multimode and birefringence characteristics of ECF. The measurement principle is that the spectra of Sagnac interference and Mach-Zehnder interference have respective sensitivities to the MFT. The magnetic sensitivity can reach 1.17â nm/mT, and the temperature sensitivity is up to -1.93â nm/°C. At the same time, the sensor has good repeatability and low detection limits of 0.41 mT and 0.25°C, respectively. It not only solves the cross-influence of temperature but also makes the spectral analysis more intuitive. The sensor has a broad development prospect in the application of MFT detection.
RESUMO
A special open-cavity Mach-Zehnder salinity sensor is presented and verified in this Letter, which has obvious advantages in salinity sensitivity and loss. The open-cavity structure is composed of a short section of etched double-side hole fiber spliced between a pair of multimode fibers and connected in series between a pair of single-mode fibers, which is the SMF-MMF-etched DSHF-MMF-SMF structure proposed in the paper. According to the experiment results, when the cavity length is about 100 µm, the salinity sensitivity of the sensing probe can reach 2 nm/, and its refractive index (RI) sensitivity can be more than 10,000 nm/RIU, while having a low loss of ${-}{15}\;{\rm dB}$ and a detection limit of 0.23. Based on its characteristics, the sensor is a prospective online monitor of ocean salinity. At the same time, it also provides a low-cost way to construct an open cavity instead of femtosecond inscribing.
RESUMO
This publisher's note contains corrections to Opt. Lett.46, 2714 (2021).OPLEDP0146-959210.1364/OL.428001.
RESUMO
A multifunctional optical fiber sensor fabricated by asymmetric offset splicing is proposed in this Letter. The light is divided into several parts at the offset interface, among which the transmitted light forms the Mach-Zehnder interference (MZI) spectrum while the reflected light forms the Fabry-Perot interference (FPI) spectrum. The online monitoring system is built to create a better light distribution at the offset interface. Theoretical analysis and experimental verification are carried out. The results of the experiment show that the proposed sensor has good characteristics of salinity and temperature, and the salinity sensitivity is as high as -2.4473nm/ in the range of 20-40; the temperature sensitivity is better than 2.17 nm/°C in the range of 28-48 °C. The two interferometers involved have different responses to temperature and salinity, contributing to the effective elimination of cross-sensitivity. The proposed optical fiber sensor has the benefits of compact size, high sensitivity, and multispectral measurement function.