scholarly journals Ultrasensitive Gas Refractometer Using Capillary-Based Mach–Zehnder Interferometer

Sensors ◽  
2020 ◽  
Vol 20 (4) ◽  
pp. 1191 ◽  
Author(s):  
Haijin Chen ◽  
Xuehao Hu ◽  
Meifan He ◽  
Pengfei Ren ◽  
Chao Zhang ◽  
...  
Keyword(s):  
Refractive Index ◽  
Fiber Optic ◽  
Low Cost ◽  
Narrow Slit ◽  
The Core ◽  
Interferometric Sensors ◽  
Crystal Fibers ◽  
Processing Techniques ◽  
Core Modes ◽  
Fiber Processing

In this paper, we report a capillary-based Mach–Zehnder (M–Z) interferometer that could be used for precise detection of variations in refractive indices of gaseous samples. The sensing mechanism is quite straightforward. Cladding and core modes of a capillary are simultaneously excited by coupling coherent laser beams to the capillary cladding and core, respectively. An interferogram would be generated as the light transmitted from the core interferes with the light transmitted from the cladding. Variations in the refractive index of the air filling the core lead to variations in the phase difference between the core and cladding modes, thus shifting the interference fringes. Using a photodiode together with a narrow slit, we could interrogate the fringe shifts. The resolution of the sensor was found to be ~5.7 × 10−8 RIU (refractive index unit), which is comparable to the highest resolution obtained by other interferometric sensors reported in previous studies. Finally, we also analyze the temperature cross sensitivity of the sensor. The main goal of this paper is to demonstrate that the ultra-sensitive sensing of gas refractive index could be realized by simply using a single capillary fiber rather than some complex fiber-optic devices such as photonic crystal fibers or other fiber-optic devices fabricated via tricky fiber processing techniques. This capillary sensor, while featuring an ultrahigh resolution, has many other advantages such as simple structure, ease of fabrication, straightforward sensing principle, and low cost.

scholarly journals Passive Fiber Optic Evanescent Wave Sensor for the Measurement of Refractive Index at Various Temperatures using a Tunable Light Source

2019 ◽  
Vol 8 (6S) ◽  
pp. 681-691
Keyword(s):  
Refractive Index ◽  
Light Source ◽  
Evanescent Wave ◽  
Fiber Optic ◽  
Fiber Optic Sensor ◽  
Depth Of Penetration ◽  
The Core ◽  
Passive Fiber ◽  
Highly Sensitive ◽  
Shaped Glass

The study of refractive index of liquids over a range of 10oC to 60oC shows very interesting results to design and develop a highly sensitive passive fiber optic sensor based on a U-shaped glass probe. The depth of penetration of light that escaping from the core of the fiber into the cladding plays a crucial role in the development of a highly sensitive fiber optic evanescent wave sensor. The depth of penetration of an optical fiber striped off its cladding is directly related to the wavelength of the light, the index of refraction of the surrounding medium, the angle of incidence of light, the bending radius and thickness of the U-shaped probe. In the design of the sensor a U-shaped glass probe is used to replace the core of the fiber in the region of sensing, the diameter of which is same as that of the cores of a pair of insensitive fibers which in-turn connected to a tunable light source and an optical detector. The sensor is highly reliable, robust and easy to configure using multimode PCS fibers and the source operating at the wavelengths of 630nm, 660nm, 820nm and 850nm.

scholarly journals Large area flexible pressure/strain sensors and arrays using nanomaterials and printing techniques

2019 ◽  
Vol 6 (1) ◽  
Author(s):  
Chithra Parameswaran ◽  
Dipti Gupta
Keyword(s):  
Low Cost ◽  
Strain Sensors ◽  
Large Area ◽  
Advanced Level ◽  
The Core ◽  
Look Back ◽  
Mems Technology ◽  
Exhaustive Study ◽  
Processing Techniques ◽  
Printing Techniques

Abstract Sensors are becoming more demanding in all spheres of human activities for their advancement in terms of fabrication and cost. Several methods of fabrication and configurations exist which provide them myriad of applications. However, the advantage of fabrication for sensors lies with bulk fabrication and processing techniques. Exhaustive study for process advancement towards miniaturization from the advent of MEMS technology has been going on and progressing at high pace and has reached a highly advanced level wherein batch production and low cost alternatives provide a competitive performance. A look back to this advancement and thus understanding the route further is essential which is the core of this review in light of nanomaterials and printed technology based sensors. A subjective appraisal of these developments in sensor architecture from the advent of MEMS technology converging present date novel materials and process technologies through this article help us understand the path further.

scholarly journals Polarization-dependent refractive index fiber-optic sensor based on the core-offset with a taper

2016 ◽  
Vol 680 ◽  
pp. 012023 ◽  
Author(s):  
Youqing Wang ◽  
Changyu Shen ◽  
Weimin Lou ◽  
Fengying Shentu
Keyword(s):  
Refractive Index ◽  
Fiber Optic ◽  
Fiber Optic Sensor ◽  
The Core ◽  
Optic Sensor

scholarly journals Dual-Core Fiber-Based Interferometer for Detection of Gas Refractive Index

Photonics ◽  
2020 ◽  
Vol 7 (4) ◽  
pp. 111
Author(s):  
Haijin Chen ◽  
Xuehao Hu ◽  
Meifan He ◽  
Qianqing Yu ◽  
Zhenggang Lian ◽  
...  
Keyword(s):  
Refractive Index ◽  
Low Cost ◽  
High Sensitivity ◽  
Narrow Slit ◽  
Hollow Core ◽  
Fiber Sensors ◽  
Air Core ◽  
Flow Through ◽  
Core Fiber ◽  
Dual Core

We demonstrate a dual-core fiber-based Mach–Zehnder interferometer that could be used for precise detection of variations in refractive indices of gaseous samples. The fiber used here have a solid germanium-doped silica core and an air core that allows gases to flow through. Coherent laser beams are coupled to the two cores, respectively, and thus excite guiding modes thereby. Interferogram would be produced as the light transmitted from the dual cores interferes. Variations in refractive index of the hollow core lead to variations in phase difference between the modes in the two cores, thus shifting the interference fringes. The fringe shifts can be then interrogated by a photodiode together with a narrow slit in front. The resolution of the sensor was found to be ~1 × 10−8 RIU, that is comparable to the highest resolution obtained by other fiber sensors reported in previous literatures. Other advantages of our sensor include very low cost, high sensitivity, straightforward sensing mechanism, and ease of fabrication.

scholarly journals In-Fiber Interferometric-Based Sensors: Overview and Recent Advances

Photonics ◽  
2021 ◽  
Vol 8 (7) ◽  
pp. 265
Author(s):  
Amalia Miliou
Keyword(s):  
Refractive Index ◽  
Fiber Optic ◽  
Operating Principle ◽  
Comprehensive Overview ◽  
Interferometric Sensors ◽  
Recent Advances ◽  
Different Types ◽  
Recent Developments

In-fiber interferometric-based sensors are a rapidly growing field, as these sensors exhibit many desirable characteristics compared to their regular fiber-optic counterparts and are being implemented in many promising devices. These sensors have the capability to make extremely accurate measurements on a variety of physical or chemical quantities such as refractive index, temperature, pressure, curvature, concentration, etc. This article is a comprehensive overview of the different types of in-fiber interferometric sensors that presents and discusses recent developments in the field. Basic configurations, a brief approach of the operating principle and recent applications are introduced for each interferometric architecture, making it easy to compare them and select the most appropriate one for the application at hand.

Low-cost fiber optic interferometric sensors

1996 ◽  
Author(s):  
Jeff Bush ◽  
Carol A. Davis ◽  
Fred P. McNair ◽  
Allen Cekorich ◽  
John A. Bostick
Keyword(s):  
Fiber Optic ◽  
Low Cost ◽  
Interferometric Sensors
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