scholarly journals Design of Fiber-Tip Refractive Index Sensor Based on Resonant Waveguide Grating with Enhanced Peak Intensity

2021 ◽  
Vol 11 (15) ◽  
pp. 6737
Author(s):  
Yicun Yao ◽  
Yanru Xie ◽  
Nan-Kuang Chen ◽  
Ivonne Pfalzgraf ◽  
Sergiy Suntsov ◽  
...  

Resonant waveguide gratings (RWG) are widely used as on-chip refractometers due to their relatively high sensitivity to ambient refractive index changes, their possibility of parallel high-throughput detection and their easy fabrication. In the last two decades, efforts have been made to integrate RWG sensors onto fiber facets, although practical application is still hindered by the limited resonant peak intensity caused by the low coupling efficiency between the reflected beam and the fiber mode. In this work, we propose a new compact RWG fiber-optic sensor with an additional Fabry-Pérot cavity, which is directly integrated onto the tip of a single-mode fiber. By introducing such a resonant structure, a strongly enhanced peak reflectance and improved figure of merit are achieved, while, at the same time, the grating size can be greatly reduced, thus allowing for spatial multiplexing of many sensors on a tip of a single multi-core fiber. This paves the way for the development of probe-like reflective fiber-tip RWG sensors, which are of great interest for multi-channel biochemical sensing and for real-time medical diagnostics.

Nanomaterials ◽  
2019 ◽  
Vol 9 (2) ◽  
pp. 306 ◽  
Author(s):  
Paulina Listewnik ◽  
Marzena Hirsch ◽  
Przemysław Struk ◽  
Matthieu Weber ◽  
Mikhael Bechelany ◽  
...  

We report the fabrication of a novel fiber-optic sensor device, based on the use of a microsphere conformally coated with a thin layer of zinc oxide (ZnO) by atomic layer deposition (ALD), and its use as a refractive index sensor. The microsphere was prepared on the tip of a single-mode optical fiber, on which a conformal ZnO thin film of 200 nm was deposited using an ALD process based on diethyl zinc (DEZ) and water at 100 °C. The modified fiber-optic microsphere was examined using scanning electron microscopy and Raman spectroscopy. Theoretical modeling has been carried out to assess the structure performance, and the performed experimental measurements carried out confirmed the enhanced sensing abilities when the microsphere was coated with a ZnO layer. The fabricated refractive index sensor was operating in a reflective mode of a Fabry–Pérot configuration, using a low coherent measurement system. The application of the ALD ZnO coating enabled for a better measurement of the refractive index of samples in the range of the refractive index allowed by the optical fiber. The proof-of-concept results presented in this work open prospects for the sensing community and will promote the use of fiber-optic sensing technologies.


2013 ◽  
Vol 284-287 ◽  
pp. 1986-1990
Author(s):  
Guei Ru Lin ◽  
Ming Yue Fu ◽  
Hao Jan Sheng ◽  
Hai Tao Sun ◽  
Wen Fung Liu

A simple, small-size, compact and high-sensitivity refractive-index sensor composed of a short no-core fiber (NCF) about 20 mm in length sandwiched between two pieces of single-mode fibers is proposed in this paper. The index measurement is experimentally demonstrated with the sensitivity of 7792.85 nm/ RIU in the range from 1.440 to 1.454 and 227.14 nm/ RIU in the range from 1.300 to 1.430. This sensing mechanism is based on the induced multi-mode interfering wavelength shift in the no-core fiber when the reflective index of the fiber outside is changed.


2012 ◽  
Vol 542-543 ◽  
pp. 901-904
Author(s):  
Ying Wu Zhou

A high sensitivity fiber-optic refractive index sensor based on the bi-conical single mode fiber tapers is proposed and demonstrated. The relationship between the resonance wavelength shift and surrounding refractive index is investigated. The experimental results show that the resonance wavelength linearly shifts toward longer wavelengths with the environmental refractive index ranging from 1.333 to 1.380. The response sensitivity increases with the decrease of the waist diameter of the tapered fiber. The proposed sensor is easily fabricated, compact and may be useful for the chemical and biotechnological industry.


2015 ◽  
Vol 40 (17) ◽  
pp. 4166 ◽  
Author(s):  
Dejun Liu ◽  
Arun Kumar Mallik ◽  
Jinhui Yuan ◽  
Chongxiu Yu ◽  
Gerald Farrell ◽  
...  

A Mach-Zehnder interferometer (MZI) built using several concatenated different structures is proposed as a refractive index sensor. This sensor is comprised of a microbubble, a section of reduced cladding fiber (RCF) and a core-offset single-mode fiber (SMF). These structures are joined together through specialized arc fusion splicing procedures. The sensor is characterised by immersing it in Cargille oil with refractive index values ranging from 1.30 to 1.39. The sensor exhibits linearity in respect to the refractive index changes, with a good sensitivity of 144.42 nm/RIU. The proposed MZI has the advantages of cost effective, repeatable fabrication, compact size and high sensitivity, which make it a promising sensor.


2021 ◽  
Vol 7 ◽  
Author(s):  
Chuanxin Teng ◽  
Yongjie Zhu ◽  
Fangda Yu ◽  
Shijie Deng ◽  
Libo Yuan ◽  
...  

A high-sensitivity Mach–Zehnder interferometer (MZI) based on the cascaded core-offset and macrobending fiber structure is proposed for refractive index (RI) measurement. The core-offset structure makes the fiber core mode couple to the cladding modes, and some of them recouple back to the fiber core at the macrobending structure forming a model interference effect. The liquid RI can be measured by monitoring the spectral shift of the modal interference. The RI sensing performances for the interferometers with different macrobending radii and core offsets are investigated experimentally. Experimental results show that when the core offset is 2 μm and the macrobending radius is 5.5 mm, the sensitivity can reach 699.95 nm/RIU for the RI of 1.43. The temperature dependence for the proposed sensor is also tested, and a temperature sensitivity of 0.112 nm/°C is obtained.


2019 ◽  
Vol 50 ◽  
pp. 13-18 ◽  
Author(s):  
Zengshan Xing ◽  
Yanzhen Wang ◽  
Li Tang ◽  
Jianhui Yu ◽  
Heyuan Guan ◽  
...  

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