Highly sensitive refractive index sensor based on two cascaded long period gratings with rotary refractive index modulation

2011 ◽  
Author(s):  
Tao Zhu ◽  
YanEn Fan ◽  
Ming Deng ◽  
Yunjiang Rao
Keyword(s):  
Refractive Index ◽  
Refractive Index Sensor ◽  
Refractive Index Modulation ◽  
Long Period ◽  
Long Period Gratings ◽  
Highly Sensitive ◽  
Index Modulation

scholarly journals Analysis of Long Period Gratings Inscribed by CO2 Laser Irradiation and Estimation of the Refractive Index Modulation

Sensors ◽  
2020 ◽  
Vol 20 (22) ◽  
pp. 6409
Author(s):  
Ana M. Rocha ◽  
Ana I. Machado ◽  
Telmo Almeida ◽  
Joana Vieira ◽  
Margarida Facão
Keyword(s):  
Refractive Index ◽  
Laser Irradiation ◽  
Refractive Index Change ◽  
Coupling Model ◽  
High Refractive Index ◽  
Refractive Index Modulation ◽  
Index Change ◽  
Long Period ◽  
Long Period Gratings ◽  
Index Modulation

Long period gratings (LPGs) inscribed in single mode fibers (SMFs) using CO2 laser irradiation were modelled numerically using the coupled mode method. The model considers the specifications of the inscription technique, such as the shape of the refractive index modulation that mimics the circularly symmetric point-to-point laser irradiation profile. A simple expression for predicting the resonant wavelength was obtained assuming a two-mode coupling model. However, to explain the spectra of the experimental LPGs, it was necessary to assume a reasonably high refractive index change and a multimode coupling model. Furthermore, using the developed model and a genetic algorithm to fit experimental resonances to simulated ones, we were able to estimate the maximum refractive index change, obtaining a value of 2.2 × 10−3, confirming the high refractive index change. The proposed model also predicts a second order resonance for this high value of refractive index change that was confirmed experimentally. Hence, with this model, we found some significant differences in the LPGs behavior when compared with conventional ones, namely, the emergence of coupling between different cladding modes and the competition of first and second order resonances which change the LPG transmission spectrum.

scholarly journals Highly Sensitive Refractive Index Sensor Based on Adiabatically Tapered Microfiber Long Period Gratings

Sensors ◽  
2013 ◽  
Vol 13 (10) ◽  
pp. 14055-14063 ◽  
Author(s):  
Wen Ji ◽  
Swee Tjin ◽  
Bo Lin ◽  
Choong Ng
Keyword(s):  
Refractive Index ◽  
Refractive Index Sensor ◽  
Long Period ◽  
Long Period Gratings ◽  
Highly Sensitive

scholarly journals Improved Refractive Index Sensitivity Utilizing Long-Period Gratings with Periodic Corrugations on Cladding

2012 ◽  
Vol 2012 ◽  
pp. 1-5 ◽  
Author(s):  
Anthony Lim ◽  
Wen Bin Ji ◽  
Swee Chuan Tjin
Keyword(s):  
Refractive Index ◽  
Cost Effective ◽  
Experimental Results ◽  
Refractive Index Sensitivity ◽  
Long Period ◽  
Specimen Collection ◽  
Long Period Gratings ◽  
Highly Sensitive ◽  
Index Sensitivity

A new structure of Long-Period Gratings (LPGs) sensor is introduced as a sensitive ambient RI sensor. This structure consists of creating periodic corrugations on the cladding of the LPG. The experimental results show that this LPG structure has good performances in terms of linearity and sensitivity and serves as a highly sensitive and cost-effective sensor. It also has the advantage of portability as the corrugation can also serve as the reservoir for the specimen collection to be tested.

A Humidity Sensor Based on Ultra-Long-Period Fiber Gratings with Asymmetric Refractive Index Modulation

2009 ◽  
Vol 36 (8) ◽  
pp. 2042-2045 ◽  
Author(s):  
宋韵 Song Yun ◽  
朱涛 Zhu Tao ◽  
饶云江 Rao Yunjiang ◽  
赵英伟 Zhao Yingwei
Keyword(s):  
Refractive Index ◽  
Humidity Sensor ◽  
Refractive Index Modulation ◽  
Fiber Gratings ◽  
Long Period ◽  
Long Period Fiber Gratings ◽  
Index Modulation

Temperature insensitive high-precision refractive-index sensor using two concatenated dual-resonance long-period gratings

2013 ◽  
Vol 38 (10) ◽  
pp. 1666 ◽  
Author(s):  
Saurabh Mani Tripathi ◽  
Wojtek J. Bock ◽  
Arun Kumar ◽  
Predrag Mikulic
Keyword(s):  
Refractive Index ◽  
High Precision ◽  
Refractive Index Sensor ◽  
Long Period ◽  
Long Period Gratings ◽  
Dual Resonance
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