scholarly journals Line Position-Dependent Effect in Line-by-Line Inscribed Fiber Bragg Gratings

Sensors ◽  
2021 ◽  
Vol 21 (21) ◽  
pp. 7231
Author(s):  
Hongye Li ◽  
Xiaofan Zhao ◽  
Binyu Rao ◽  
Meng Wang ◽  
Baiyi Wu ◽  
...  
Keyword(s):  
Fiber Bragg Gratings ◽  
Bragg Gratings ◽  
Direct Writing ◽  
Line Position ◽  
Low Loss ◽  
The Core ◽  
Cladding Mode ◽  
Application Requirements ◽  
First Time ◽  
Line Positions

Line-by-line direct writing by femtosecond laser has been proved to be a simple and effective method for the fabrication of low-loss fiber Bragg gratings (FBGs), and is more flexible compared with the traditional ultraviolet exposure method. In this paper, the line-position-dependent characteristics of cladding modes coupling in line-by-line FBGs have been studied, to the best of our knowledge, for the first time. Both theoretical and experimental results show that off-center inscribing could compress the bandwidth of the Bragg resonance and excite more abundant cladding mode coupling, in which the core-guided fundamental mode would couple to the cladding-guided LP0n and LP1n simultaneously. By aligning the line positions across the core region, the first apodized line-by-line FBG was achieved. This work enriches the theories of line-by-line FBGs and provides an inscription guidance to meet different application requirements.

Femtosecond direct-writing of low-loss fiber Bragg gratings using a continuous core-scanning technique

2013 ◽  
Vol 38 (11) ◽  
pp. 1918 ◽  
Author(s):  
Robert J. Williams ◽  
Ria G. Krämer ◽  
Stefan Nolte ◽  
Michael J. Withford
Keyword(s):  
Fiber Bragg Gratings ◽  
Bragg Gratings ◽  
Direct Writing ◽  
Low Loss ◽  
Scanning Technique

Wavelength tunable fiber Bragg gratings fabricated by stress annealing assisted femtosecond laser direct writing

2021 ◽  
Vol 61 ◽  
pp. 102427
Author(s):  
Xiaoyan Sun ◽  
Zikun Chang ◽  
Li Zeng ◽  
Xinran Dong ◽  
Youwang Hu ◽  
...  
Keyword(s):  
Femtosecond Laser ◽  
Fiber Bragg Gratings ◽  
Bragg Gratings ◽  
Direct Writing ◽  
Laser Direct Writing ◽  
Wavelength Tunable

Permanent Photoinduced Refractive-Index Changes for Bragg Gratings in Silicate Glass Waveguides and Fibers

MRS Bulletin ◽  
1998 ◽  
Vol 23 (11) ◽  
pp. 36-41 ◽  
Author(s):  
Jacques Albert
Keyword(s):  
Refractive Index ◽  
Silicate Glass ◽  
Practical Importance ◽  
Fiber Bragg Gratings ◽  
Optical Filters ◽  
Bragg Gratings ◽  
Research Centre ◽  
Lightwave Technology ◽  
The Core ◽  
Wavelength Multiplexing

In 1978 Kenneth Hill of the Communications Research Centre in Ottawa discovered that intense blue light propagating inside the core of a germanium-doped silicate glass fiber modified the core refractive index sufficiently to form a measurable permanent hologram. Because germanium-doped silica is the material of choice for the core of most optical fiber in use today for optical communications, this “photosensitive” phenomenon has been recognized as having tremendous practical importance. Fiber Bragg gratings in particular form excellent narrow-band optical filters with a multitude of applications: sensors, fiber laser mirrors, wavelength multiplexers (the acronym for wavelength multiplexing and demultiplexing in systems is WDM), and dispersion control devices—to name a few that are already commercially available. The importance of this field can be verified in just about any current issue of journals related to lightwave technology and applications of optics. Fiber Bragg gratings are mentioned everywhere. In fact a recent issue of the Journal of Lightwave Technology is entirely devoted to this topic (and to poling of silica, a field reviewed by W. Margulis in this issue).

scholarly journals Cladding mode coupling in highly localized fiber Bragg gratings II: complete vectorial analysis

2012 ◽  
Vol 20 (19) ◽  
pp. 21434 ◽  
Author(s):  
Jens U. Thomas ◽  
Nemanja Jovanovic ◽  
Ria G. Krämer ◽  
Graham D. Marshall ◽  
Michael J. Withford ◽  
...  
Keyword(s):  
Mode Coupling ◽  
Fiber Bragg Gratings ◽  
Bragg Gratings ◽  
Cladding Mode

scholarly journals Femtosecond laser direct-written fiber Bragg gratings with high reflectivity and low loss at wavelengths beyond 4 µm

2020 ◽  
Vol 45 (15) ◽  
pp. 4316 ◽  
Author(s):  
Gayathri Bharathan ◽  
Toney Teddy Fernandez ◽  
Martin Ams ◽  
Jean-Yves Carrée ◽  
Samuel Poulain ◽  
...  
Keyword(s):  
Femtosecond Laser ◽  
Fiber Bragg Gratings ◽  
Bragg Gratings ◽  
Low Loss ◽  
High Reflectivity

scholarly journals Sapphire-Derived Fiber Bragg Gratings for High Temperature Sensing

Crystals ◽  
2021 ◽  
Vol 11 (8) ◽  
pp. 946
Author(s):  
Qi Guo ◽  
Zhixu Jia ◽  
Xuepeng Pan ◽  
Shanren Liu ◽  
Zhennan Tian ◽  
...  
Keyword(s):  
Refractive Index ◽  
High Temperature ◽  
Spectral Characteristics ◽  
Fiber Bragg Gratings ◽  
Single Mode ◽  
Bragg Gratings ◽  
Temperature Sensing ◽  
Direct Writing ◽  
Core Diameter ◽  
Application Range

In this paper, a sapphire-derived fiber (SDF) with a core diameter of 10 μm and a cladding diameter of 125 μm is fabricated by the melt-in-tube method, and fiber Bragg gratings (FBGs) with reflectivity over 80% are prepared by the femtosecond laser point-by-point direct writing method. By analyzing the refractive index distribution and reflection spectral characteristics of the SDF, it can be seen that the SDF is a graded refractive index few-mode fiber. In order to study the element composition of the SDF core, the end-face element distribution of the SDF is analyzed, which indicates that element diffusion occurred between the core and the cladding materials. The temperature and stress of the SDF gratings are measured and the highest temperature is tested to 1000 °C. The temperature and strain sensitivities are 15.64 pm/°C and 1.33 pm/με, respectively, which are higher than the temperature sensitivity of the quartz single-mode fiber. As a kind of special fiber, the SDF expands the application range of sapphire fiber, and has important applications in the fields of high-temperature sensing and high-power lasers.

scholarly journals Fabrication and Characterization of Line-by-Line Inscribed Tilted Fiber Bragg Gratings Using Femtosecond Laser

Sensors ◽  
2021 ◽  
Vol 21 (18) ◽  
pp. 6237
Author(s):  
Hongye Li ◽  
Xiaofan Zhao ◽  
Binyu Rao ◽  
Meng Wang ◽  
Baiyi Wu ◽  
...  
Keyword(s):  
Fiber Bragg Gratings ◽  
Bragg Gratings ◽  
Fiber Axis ◽  
Central Plane ◽  
Tilted Angle ◽  
Fabrication And Characterization ◽  
Cladding Mode ◽  
Basic Characteristics ◽  
Birefringence Effect

In this paper, we studied the basic characteristics of tilted fiber Bragg gratings (TFBGs), inscribed line-by-line. Experimental results showed that if the TFBGs were located within different planes parallel to the fiber axis, the spectra performed differently. For 2°TFBG, if it was located near the central plane, the Bragg resonance was stronger than ghost mode resonance, and the order reversed if it was located near the boundary between core and cladding. As the tilted angle increased, the range of cladding mode resonance increased. When the tilted angle was larger than 12°, the birefringence effect was observed. Based on the birefringence phenomenon, torsion characteristics were experimentally studied; the sensitivity was about 0.025 dB/degree in the linear variation range. The harmonic order of TFBGs also affected the transmission spectrum. Leaky mode resonance was observed in the 8th order TFBG, and torsion (or polarization) influenced the spectrum of the 8th order TFBG. Our research represented the theory of line-by-line inscribed TFBGs and provided an inscription guidance for TFBGs.

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