Responses of a long-period grating fabricated in a graded-index optical fiber to temperature and refractive-index changes

2006 ◽  
Vol 26 (2-3) ◽  
pp. 457-461 ◽  
Author(s):  
M. Chomát ◽  
D. Berková ◽  
V. Matějec ◽  
I. Kašík ◽  
J. Kaňka ◽  
...  
Keyword(s):  
Refractive Index ◽  
Optical Fiber ◽  
Long Period Grating ◽  
Graded Index ◽  
Long Period ◽  
Index Changes

scholarly journals Optical Fiber Interferometers Based on Arc-Induced Long Period Gratings at INESC TEC

Sensors ◽  
2021 ◽  
Vol 21 (21) ◽  
pp. 7400
Author(s):  
Paulo Caldas ◽  
Gaspar Rego
Keyword(s):  
Refractive Index ◽  
Optical Fiber ◽  
Cavity Length ◽  
Fiber Optic ◽  
Fiber Diameter ◽  
Long Period Grating ◽  
Long Period ◽  
Long Period Gratings ◽  
Cladding Mode ◽  
Mode A

In this work, we review the most important achievements of an INESC TEC long-period-grating-based fiber optic Michelson and Mach–Zehnder configuration modal interferometer with coherence addressing and heterodyne interrogation as a sensing structure for measuring environmental refractive index and temperature. The theory for Long Period Grating (LPG) interferometers and coherence addressing and heterodyne interrogation is presented. To increase the sensitivity to external refractive index and temperature, several LPG interferometers parameters are studied, including order of cladding mode, a reduction of the fiber diameter, different type of fiber, cavity length and the antisymmetric nature of cladding modes.

Multi-parameter Simultaneously Sensing Based on an Optimized Concatenated FBG with LPG

2015 ◽  
Vol 36 (2) ◽  
Author(s):  
Yong Chen ◽  
Bao-lin Liu ◽  
Huan-lin Liu ◽  
Kai Yang ◽  
Li-juan Chen
Keyword(s):  
Optical Fiber ◽  
Fiber Bragg Grating ◽  
Reflection Spectrum ◽  
Optical Fiber Sensor ◽  
Reference Value ◽  
Fiber Sensor ◽  
Bragg Grating ◽  
Long Period Grating ◽  
Long Period ◽  
Index Changes

AbstractWe analyze an optical fiber sensor based on a concatenated fiber Bragg grating (FBG) with long period grating (LPG) with transfer matrix method and experiment. First, we optimize parameters of concatenated structure in the method of simulation and discuss the influence that the lengths, periods and dc induced index changes of FBG and LPG and length of optical fiber between LPG and FBG has to influence reflection spectrum. Second, based on the optimized parameters for concatenated structure, fabricate such structure and use it to monitor concentration and temperature simultaneously. Simulation result proves that increasing the lengths of FBG and LPG properly, and length of optical fiber between LPG and FBG fixed in 20 mm, more clearly reflection spectrum can be obtained. Experiment result shows a novel optical fiber sensor based on a concatenated strong fiber Bragg grating with a weak long period grating (CLBG) device can be used to monitor concentration and temperature simultaneously. The result of research has reference value in multi-parameter simultaneously sensing.

A Long Period Grating Sensor Based on Helical Capillary Optical Fiber

2021 ◽  
pp. 1-1
Author(s):  
Hongchang Deng ◽  
Rui Wang ◽  
Xiaowen Jiang ◽  
Chuanxin Teng ◽  
Ronghui Xu ◽  
...  
Keyword(s):  
Optical Fiber ◽  
Long Period Grating ◽  
Long Period

On-line tests of an optical fiber long-period grating subjected to gamma irradiation

2014 ◽  
Author(s):  
D. Sporea ◽  
A. Stancalie ◽  
D. Negut ◽  
G. Pilorget ◽  
S. Delepine-Lesoille ◽  
...  
Keyword(s):  
Optical Fiber ◽  
Gamma Irradiation ◽  
Long Period Grating ◽  
Long Period ◽  
On Line
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