Design of Long-Period Fiber Grating Refractometric Sensors With Linear Response by a Genetic Algorithm

Flores-Llamas, Ignacio; Svyryd, V.; Khotiaintsev, S.

doi:10.1109/jsen.2008.926525

Cited by 11 publications

(14 citation statements)

References 21 publications

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“…The study was conducted on two non-uniform LPFG designed for refractometric applications [5][6][7] . First, LPFG transmission spectra were calculated for nominal period Λ m , coupling coefficient κ m, i and phase shift between the adjacent sections ϕ m .…”

Section: Methodsmentioning

confidence: 99%

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Fabrication tolerances in long-period fiber grating refractometric sensors

Beltrán-Hernández

Khotiaintsev

2013

SPIE Proceedings

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This work focuses on the results and analyses performed on long-period optical-fiber gratings (LPFG) designed for use as refractometric sensors. The study was conducted with non-uniform LPFG specially designed for refractometric applications. First, LPFG transmission spectra were calculated for nominal period, propagation constant of the cladding mode and phase shift between the adjacent LPFG sections. Then, a random variation of the above parameters was introduced and the effect of this variation on the transmission spectrum of the LPFG, with the external refractive index as parameter, was evaluated. Finally, a change in the resonant wavelength against the external refractive index was investigated under random variation of parameters. We have found that in some long-period fiber grating refractometric sensors fabrication tolerances should as stringent as 0.2 % of nominal parameter. The methodology of tolerance analysis and quantitative data obtained in this work might be useful in establishing tolerances for fabrication parameters of longperiod fiber grating refractometric sensors.

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Section: Methodsmentioning

confidence: 99%

“…Therefore, the LPFG optical loss is spectrally selective. Moreover, LPFG transmission spectrum is affected by the refractive index of the external medium, because this quantity affects the propagation constant of the cladding modes [3][4][5][6][7][8]9 . A variation in the external refractive index n changes the LPFG resonant wavelength …”

Section: Introductionmentioning

confidence: 99%

Fabrication tolerances in long-period fiber grating refractometric sensors

Beltrán-Hernández

Khotiaintsev

2013

SPIE Proceedings

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“…6 In literature, these displacements in CMRW for ARIs greater than cladding RI have been investigated to evaluate the RI response of normal cladding LPFG. [7][8][9][10] But, the CMRW displacements with ARI are found smaller which outcomes low RI sensitivity, and discourage the LPFG application in sensing the ARI. However, LPFG has shown improvement in its sensitivity for ARIs less than cladding RI with an increase in differential EIR at the reduced cladding and fixed period.…”

Section: Introductionmentioning

confidence: 97%

“…According to phase match equation, CMRW displacement for an ARI is dependent on differential EIR and LPFG period 6 . In literature, these displacements in CMRW for ARIs greater than cladding RI have been investigated to evaluate the RI response of normal cladding LPFG 7‐10 . But, the CMRW displacements with ARI are found smaller which outcomes low RI sensitivity, and discourage the LPFG application in sensing the ARI.…”

Section: Introductionmentioning

confidence: 99%

Quantitative analysis of optical modes in sensing a medium of the higher refractive index through long‐period fiber grating

Prashar

Singh

Sood³

et al. 2021

Micro & Optical Tech Letters

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The response of a long-period fiber grating (LPFG) based refractometric sensor is directly related to the optical modes' effective index of refraction (EIR). In this paper, the quantitative behavior of EIR is investigated with LPFG surrounded dielectric medium's refractive index (RI) higher than cladding RI and cladding radius. To analyze the impact on EIR, the 2-layer and 3-layer fiber structure-based mathematical models have been introduced. In the past literature, the interaction of the ambient medium with the core mode field is rarely investigated. Therefore, such studies have been considered and as a result, a significant impact on core mode EIR has been observed. The influence of ambient-medium RI (ARI = 1.458-1.738) on EIR is found ascended for its value near to cladding RI at normal cladding radius. However, the range of influencing ARIs has been extended with mode order and cladding radius reduction. This study encourages the measuring of LPFG RI response for the aforesaid ARI range in terms of shift in coupled mode resonance wavelength and improves the precision in sensing ARI.

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“…Different studies have experimentally measured such shifts in CMRW with ARI (when ARIs higher than cladding RI) to investigate the RI sensitivity of standard cladding LPFG (Flores-Llamas et al 2008;Hou et al 2001;James et al 2002;Libish et al 2012;Patrick et al 1998). However, the smaller shifts in CMRW with ARI indicate the lower RI sensitivity as well as the resolution of an LPFG sensor.…”

Section: Introductionmentioning

confidence: 99%

Performance analysis of cladding radius on spectral behaviour and sensitivity of LPFG with ambient refractive index higher than cladding region

Prashar

Singh

Sood³

2021

Opt Quant Electron

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For ambient refractive index (ARI) higher than cladding region, the refractive index (RI) sensitivity of long-period fiber grating (LPFG) measured in terms of the shift in the cladding mode resonance wavelength (CMRW) is very low. This may be due to the occurrence of a small CMRW shift with a change in ARI. This paper emphasizes the effect of cladding radius reduction as well as cladding mode-order over the spectral behavior, RI response and figure of merit of LPFG for such ARIs. Therefore, mathematical approaches designed on three-layer and two-layer fiber geometries are employed on single-mode optical fiber (SMF28e) to estimate optical modes. The influence of cladding radius reduction (from 62.5 to 32.5 µm) on spectral profile and RI sensitivity is analyzed for three cladding modes (HE 13, HE 14 and HE 15 ). The spectral behavior of all three modes for the ARI range (1.458-1.738) has described the shifting of CMRW towards longer wavelengths. From the analysis, the larger shifts in CMRW with ARIs have been shown by HE 15 cladding mode at a cladding radius of 32.5 µm as compared to normal cladding LPFG. Moreover, the spectral bands of ARIs near to cladding index have shown very low differentiation in attenuation spectrum depths at reduced cladding radius.

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Design of Long-Period Fiber Grating Refractometric Sensors With Linear Response by a Genetic Algorithm

Cited by 11 publications

References 21 publications

Fabrication tolerances in long-period fiber grating refractometric sensors

Fabrication tolerances in long-period fiber grating refractometric sensors

Quantitative analysis of optical modes in sensing a medium of the higher refractive index through long‐period fiber grating

Performance analysis of cladding radius on spectral behaviour and sensitivity of LPFG with ambient refractive index higher than cladding region

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