Photonics 2025, 12(1), 32; https://doi.org/10.3390/photonics12010032 (registering DOI) - 3 Jan 2025
Abstract
In the realm of advanced optical fiber sensing (OFS) technologies, Fiber Bragg Grating (FBG) has garnered widespread application in the monitoring of temperature, strain, and external refractive indices, particularly within high-radiation environments such as high-energy physics laboratories, nuclear facilities, and space satellites. Notably,
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In the realm of advanced optical fiber sensing (OFS) technologies, Fiber Bragg Grating (FBG) has garnered widespread application in the monitoring of temperature, strain, and external refractive indices, particularly within high-radiation environments such as high-energy physics laboratories, nuclear facilities, and space satellites. Notably, FBGs inscribed using femtosecond lasers are favored for their superior radiation resistance. Among various inscription techniques, the point-by-point (PbP) and line-by-line (LbL) methods are predominant; however, their comparative impacts on radiation durability have not been adequately explored. In this research, FBGs were inscribed on a single-mode fiber using both the PbP and LbL methods, and subsequently subjected to a total irradiation dose of 5.04 kGy (radiation flux of 2 rad/s) over 70 h in a 60Co-γ radiation environment. By evaluating the changes in temperature- and strain-sensing performance of the FBG pre-irradiation and post-irradiation, this study identifies a more favorable technique for writing anti-irradiation FBG sensors. Moreover, an analysis into the radiation damage mechanisms in optical fibers, alongside the principles of femtosecond laser inscription, provides insights into the enhanced radiation resistance observed in femtosecond laser-written FBGs. This study thus furnishes significant guidance for the development of highly radiation-resistant FBG sensors, serving as a critical reference in the field of high-performance optical fiber sensing technologies.
Full article
(This article belongs to the Special Issue Emerging Trends in Optical Fiber Sensors and Sensing Techniques)
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Show Figures
Figure 1
Figure 1
<p>Schematic diagram of FBG sensing principle.</p> Full article ">Figure 2
<p>Schematic of femtosecond inscription FBG.</p> Full article ">Figure 3
<p>Micrograph of writing FBG by femtosecond laser.</p> Full article ">Figure 4
<p>Schematic of sensing experiment.</p> Full article ">Figure 5
<p>Sensing experiment setup.</p> Full article ">Figure 6
<p>Schematic of radiation experiment.</p> Full article ">Figure 7
<p>Temperature-sensing spectral diagram and central wavelength drift diagram written by the PbP method before irradiation: (<b>a</b>) 3d spectrum of heating; (<b>b</b>) center wavelength drift diagram of heating; (<b>c</b>) 3d spectrum of cooling; (<b>d</b>) center wavelength drift diagram of cooling.</p> Full article ">Figure 8
<p>Temperature-sensing spectral diagram and central wavelength drift diagram written by the PbP method after irradiation: (<b>a</b>) 3d spectrum of heating; (<b>b</b>) center wavelength drift diagram of heating; (<b>c</b>) 3d spectrum of cooling; (<b>d</b>) center wavelength drift diagram of cooling.</p> Full article ">Figure 9
<p>The strain-sensing spectrum and the central wavelength drift diagram written by the PbP method before irradiation: (<b>a</b>) 3d spectrum of applying strain; (<b>b</b>) center wavelength drift diagram of applying strain; (<b>c</b>) 3d spectrum of unloading strain; (<b>d</b>) center wavelength drift diagram of unloading strain.</p> Full article ">Figure 10
<p>The strain-sensing spectrum and the central wavelength drift diagram written by the PbP method after irradiation: (<b>a</b>) 3d spectrum of applying strain; (<b>b</b>) center wavelength drift diagram of applying strain; (<b>c</b>) 3d spectrum of unloading strain; (<b>d</b>) center wavelength drift diagram of unloading strain.</p> Full article ">
<p>Schematic diagram of FBG sensing principle.</p> Full article ">Figure 2
<p>Schematic of femtosecond inscription FBG.</p> Full article ">Figure 3
<p>Micrograph of writing FBG by femtosecond laser.</p> Full article ">Figure 4
<p>Schematic of sensing experiment.</p> Full article ">Figure 5
<p>Sensing experiment setup.</p> Full article ">Figure 6
<p>Schematic of radiation experiment.</p> Full article ">Figure 7
<p>Temperature-sensing spectral diagram and central wavelength drift diagram written by the PbP method before irradiation: (<b>a</b>) 3d spectrum of heating; (<b>b</b>) center wavelength drift diagram of heating; (<b>c</b>) 3d spectrum of cooling; (<b>d</b>) center wavelength drift diagram of cooling.</p> Full article ">Figure 8
<p>Temperature-sensing spectral diagram and central wavelength drift diagram written by the PbP method after irradiation: (<b>a</b>) 3d spectrum of heating; (<b>b</b>) center wavelength drift diagram of heating; (<b>c</b>) 3d spectrum of cooling; (<b>d</b>) center wavelength drift diagram of cooling.</p> Full article ">Figure 9
<p>The strain-sensing spectrum and the central wavelength drift diagram written by the PbP method before irradiation: (<b>a</b>) 3d spectrum of applying strain; (<b>b</b>) center wavelength drift diagram of applying strain; (<b>c</b>) 3d spectrum of unloading strain; (<b>d</b>) center wavelength drift diagram of unloading strain.</p> Full article ">Figure 10
<p>The strain-sensing spectrum and the central wavelength drift diagram written by the PbP method after irradiation: (<b>a</b>) 3d spectrum of applying strain; (<b>b</b>) center wavelength drift diagram of applying strain; (<b>c</b>) 3d spectrum of unloading strain; (<b>d</b>) center wavelength drift diagram of unloading strain.</p> Full article ">
