Analysis of phase-shifted long-period fiber gratings

Ke, Hong; Chiang, Kin Seng; Peng, Jihu

doi:10.1109/68.726761

Cited by 89 publications

(28 citation statements)

References 7 publications

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“…The more the number of phase shift is, the wider the bandwidth of pass band is. The results of multi--phase-shifted and coated LPFG are similar to the simulation of uncoated LPFG studied by Ke H et al [8] .…”

Section: α =supporting

confidence: 86%

“…Phase-shifted LPFG is designed by introducing phase shifts in two uniform LPG, which attracted people's much attention due to its great design flexibility [6,7] . Ke H et al analyzed the transmission spectrum of double-clad phase-shifted LPFG, and optimized the spectra characteristics by adjusting the number and the location of the phase shifts [8] .…”

Section: Introductionmentioning

confidence: 99%

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Filtering Characteristics of Coated Phase Shifted Long-Period Fiber Grating

Jiang-tao

Zhao

2009

2009 Symposium on Photonics and Optoelectronics

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The filtering characteristics of coated phase-shifted long-period fiber grating (LPFG) is analyzed by the coupledmode theory together with the transfer matrix method. The effects of introducing single and multiple phase shifts at various locations along a LPFG are analyzed, and the influences of the film parameters on the spectral characteristics are also studied. It is shown that the number, location and value of the phase shifts will affect the LPFG filtering characteristics. The loss peak of transmission spectrum decreases with the increase of film thickness, and the peak position shifts with the film refractive index. Compared with the non-coated phase-shifted LPFG, the coated phase-shifted LPFG not only has the similar desirable filtering characteristics, but also has a flexible adjustment ability to transmission properties.

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Section: α =supporting

confidence: 86%

Section: Introductionmentioning

confidence: 99%

Filtering Characteristics of Coated Phase Shifted Long-Period Fiber Grating

Jiang-tao

Zhao

2009

2009 Symposium on Photonics and Optoelectronics

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“…The theory of the PSLPFG has also been described [16]. All of the PSLPFGs reported so far are written by using the UV exposure method in photosensitive fibers.…”

Section: Strain and Temperature Sensors Based On Phase-shifted Lpfgs [14]mentioning

confidence: 98%

Recent progress in long-period fiber grating sensors written by high-frequency CO 2 laser pulses

Rao

2005

SPIE Proceedings

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In this paper, we report recent progress in long-period fiber gratings (LPFGs) fabricated by using a new writing technique that is mainly based on the thermal shock effect of focused high-frequency CO 2 laser pulses at several kHz. The writing mechanism of this technique is reported for the first time to our knowledge. Novel sensor systems for low-cost measurement of strain and dynamic transverse load are proposed and demonstrated. In addition, phase-shifted LPFGs are fabricated and used for sensing of strain and temperature. Finally, the etching characteristics of these LPFG sensors are investigated.

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“…Phase-shifted LPFG is designed by introducing phase shifts in two uniform LPFG, which attracted people's much attention due to its great design flexibility [6,7] . Ke H et al [8] analyzed the transmission spectrum of double-clad phase-shifted LPFG, and optimized the spectra characteristics by adjusting the number and the location of the phase shifts.Recently people paid much attention on coating an overlay of the thin film on the fiber cladding of the grating region. This kind of LPFG is sensitive to an external medium (gases or solutions).…”

mentioning

confidence: 99%

Transmission spectra of coated phase shifted long-period fiber gratings

Zhao

Zhang

2009

Optoelectron. Lett.

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The transmission spectrum of the coated phase-shifted long-period fiber gratings (LPFGs) with single and multiple phase shifts is analyzed by the coupled-mode theory and the transfer matrix method, and the influences of the film parameters on the spectral characteristics are also studied. It is shown that these parameters will affect the LPFG filtering characteristics.The loss peak of transmission spectrum decreases with the increase of film thickness, and the peak position shifts with the film refractive index. Compared with the non-coated phase-shifted LPFG, the coated one has the similar desirable filtering characteristics, and it has a flexible ability to adjust the transmission properties.Long-period fiber grating (LPFG) consists of a single-mode fiber, whose core refractive index is periodically modulated. LPFG has a much longer period than fiber Bragg grating (FBG). LPFG has many advantages over FBG, such as simple structure, weak back reflection, low insertion loss and cheap price. So, LPFG has been applied widely in gain equalizers of erbium-doped fiber amplifier (EDFA) [1] , filters [2] , fiber sensors [3] and so on.The transmission spectrum of an uniform LPFG has only one loss peak for specified cladding mode at certain waveband. The central wavelength, intensity and bandwidth of loss peak can be only changed by adjusting the grating structure parameters, such as grating length, grating period and core index modulation [4,5] . So there is a lack of design flexibility for various spectral requirements. Phase-shifted LPFG is designed by introducing phase shifts in two uniform LPFG, which attracted people's much attention due to its great design flexibility [6,7] . Ke H et al. [8] analyzed the transmission spectrum of double-clad phase-shifted LPFG, and optimized the spectra characteristics by adjusting the number and the location of the phase shifts.Recently people paid much attention on coating an overlay of the thin film on the fiber cladding of the grating region. This kind of LPFG is sensitive to an external medium (gases or solutions). Nicholas D R [9] coated an organic material thin film on the cladding of the LPFG using the LamgmuirBlodgett technique, and studied the influence of the thickness of the overlay material upon the LPFG response. Gu Z T et al. [10,11] deposited the sensitive films on the double-clad LPFG, and fabricated a LPFG film sensor for detection of C 2 H 5 OH. It can be predicted that the transmission spectrum of the phase-shifted LPFG, on which a sensitive thin film is deposited, should show new characteristics. In this paper the transmission spectrum of the coated phase-shifted LPFG is studied based on coupled-mode equations together with the transfer matrix method. The spectrum characteristics are analyzed through introducing single and multiple phase shifts at various locations in this LPFG. And the influences of the film parameters on the spectral characteristics of phase-shifted LPFG are also studied, which has an immensely guiding role for the optimization of the transmiss...

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Analysis of phase-shifted long-period fiber gratings

Cited by 89 publications

References 7 publications

Filtering Characteristics of Coated Phase Shifted Long-Period Fiber Grating

Filtering Characteristics of Coated Phase Shifted Long-Period Fiber Grating

Recent progress in long-period fiber grating sensors written by high-frequency CO 2 laser pulses

Transmission spectra of coated phase shifted long-period fiber gratings

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