Femtosecond inscription of phase-shifted gratings by overlaid fiber Bragg gratings

Shamir, Avishay; Ishaaya, Amiel A.

doi:10.1364/ol.41.002017

Cited by 16 publications

(3 citation statements)

References 15 publications

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“…Alternatively, phase-shifted FBGs can be fabricated using infrared (IR) femtosecond (fs) lasers. The primary techniques in this case are based on point-by-point/line-by-line writing [6,14,15] and displacing a uniform phase mask during the inscription [16,17]. Uniform phase masks were also used to produce phase-shifted FBGs when i) a uniform FBG was overexposed in the center [18], ii) the central part of the fs-laser beam was blocked [19] and iii) a uniform FBG was written in a length of fiber that incorporates a fusion splice [20].…”

Section: Introductionmentioning

confidence: 99%

High-temperature stable π-phase-shifted fiber Bragg gratings inscribed using infrared femtosecond pulses and a phase mask

Hnatovsky¹,

Grobnic²,

Mihailov³

2018

Opt. Express

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Type II π-phase-shifted Bragg gratings stable up to ~1000°C are written inside a standard single mode silica optical fiber (SMF-28) with infrared femtosecond pulses and a special phase mask. Inscription through the protective polyimide fiber coating is also demonstrated. The birefringence of the Bragg gratings and, as a result, the polarization dependence of their spectra are strongly affected by the femtosecond laser polarization. Using optimized writing conditions, the full width at half maximum of the π-phase-shifted passband feature can be ~30 pm in transmission, while the polarization-dependent shift of its central wavelength can be less than 8 pm, for a 7 mm long grating structure. This makes such gratings a unique tool for high-resolution measurements of temperature, load and vibration in extreme temperature environments.

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Section: Introductionmentioning

confidence: 99%

High-temperature stable π-phase-shifted fiber Bragg gratings inscribed using infrared femtosecond pulses and a phase mask

Hnatovsky¹,

Grobnic²,

Mihailov³

2018

Opt. Express

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“…Moreover, only one uniform PM is used for the whole process. In the past, only two FBGs with a slight wavelength shift were inscribed at the same spot to achieve phase-shifted gratings [11,16,25,26]. In addition, such a grating array of five FBGs can be used to simultaneously measure temperature and or strain of a specific spot with different wavelengths.…”

Section: Introductionmentioning

confidence: 99%

Femtosecond Inscription of a Fiber Bragg Grating Spectral Array in the Same Spatial Location

Halstuch

Ishaaya

2023

Sensors

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A five fiber Bragg grating (FBG) array is inscribed at the same spot with a single uniform phase-mask (PM). The inscription setup consists of a near-infrared femtosecond laser, a PM, a defocusing spherical lens and a cylindrical focusing lens. The tunability of the center Bragg wavelength is achieved by a defocusing lens, and by translating the PM, which results in a different magnification of the PM. A first FBG is inscribed, followed by four cascading FBGs, which are inscribed exactly at the same spot only after the translation of the PM. The transmission and reflection spectra of this array are measured, showing a second-order Bragg wavelength at ~1.56 µm with a transmission dip of ~−8 dB. The spectral wavelength shift between each consecutive FBG is ~2.9 nm, and the total wavelength shift is ~11.7 nm. The reflection spectrum of the third-order Bragg wavelength is measured at ~1.04 µm, showing a wavelength separation of ~1.97 nm between neighboring FBGs, and the total spectral span between the first FBG and the last one is ~8 nm. Finally, the wavelength sensitivity to strain and temperature is measured.

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“…It is found that more neighboring resonant peaks could be obtained in the spectrum by introducing phase changes in the center of grating [ 2 ]. Then, the PS-FBG has received a great deal of attention for its narrow linewidth, multiple channels, and flexible combination, and has been widely used in the fields of optical communication, optical calculation, and optical sensing as an emerging optical passive device [ 3 , 4 , 5 , 6 ].…”

Section: Introductionmentioning

confidence: 99%

Phase-Shifted Eccentric Core Fiber Bragg Grating Fabricated by Electric Arc Discharge for Directional Bending Measurement

Ouyang

Liu

et al. 2018

Sensors

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A phase-shifted eccentric core fiber Bragg grating (PS-ECFBG) fabricated by electric arc discharge (EAD) is presented and demonstrated. It is composed of a fraction of eccentric core fiber fusion spliced in between two pieces of commercial single mode fibers, where a PS-FBG was written. The EAD in this work could flexibly change the amount of phase-shift by changing the discharge number or discharge duration. Because of the offset location of the eccentric core and the ultra-narrow resonant peak of the PS-ECFBG, it has a higher accuracy for measuring the directional bend. The elongation and compression of the eccentric core keep the magnitude of phase shift still unchanged during the bending process. The bending sensitivities of the PS-ECFBG at two opposite most sensitive directions are 57.4 pm/m−1 and −51.5 pm/m−1, respectively. Besides, the PS-ECFBG has the potential to be a tunable narrow bandpass filter, which has a wider bi-directional adjustable range because of the bending responses. The strain and temperature sensitivities of the PS-ECFBG are experimentally measured as well, which are 0.70 pm/με and 8.85 pm/°C, respectively.

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Femtosecond inscription of phase-shifted gratings by overlaid fiber Bragg gratings

Cited by 16 publications

References 15 publications

High-temperature stable π-phase-shifted fiber Bragg gratings inscribed using infrared femtosecond pulses and a phase mask

High-temperature stable π-phase-shifted fiber Bragg gratings inscribed using infrared femtosecond pulses and a phase mask

Femtosecond Inscription of a Fiber Bragg Grating Spectral Array in the Same Spatial Location

Phase-Shifted Eccentric Core Fiber Bragg Grating Fabricated by Electric Arc Discharge for Directional Bending Measurement

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