Speed of Light in Hollow-Core Photonic Bandgap Fiber Approaching That in Vacuum
A Fresnel mirror is introduced at a hollow-core photonic bandgap fiber end by fusion splicing a short single-mode fiber segment, to reflect the light backward to an optical frequency domain reflectometry. The backward Fresnel reflection is used as a probe light to achieve light speed measurement wit...
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| Format: | Article |
| Language: | English |
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MDPI AG
2024-10-01
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| Series: | Sensors |
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| Online Access: | https://www.mdpi.com/1424-8220/24/21/6954 |
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| author | Xiaolu Cao Mingming Luo Jianfei Liu Jie Ma Yundong Hao Yange Liu |
| author_facet | Xiaolu Cao Mingming Luo Jianfei Liu Jie Ma Yundong Hao Yange Liu |
| author_sort | Xiaolu Cao |
| collection | DOAJ |
| description | A Fresnel mirror is introduced at a hollow-core photonic bandgap fiber end by fusion splicing a short single-mode fiber segment, to reflect the light backward to an optical frequency domain reflectometry. The backward Fresnel reflection is used as a probe light to achieve light speed measurement with a high resolution and a high signal-to-noise ratio. Thus, its group velocity is obtained with the round-trip time delay as well as the beat frequency at the reflection peak. Multiple Fresnel peaks are observed from 2180.00 Hz to 13,988.75 Hz, corresponding to fusion-spliced hollow-core fiber segments with different lengths from 0.2595 m to 1.6678 m, respectively. The speed of light in the air guidance is calculated at 2.9753 × 10<sup>8</sup> m/s, approaching that in vacuum, which is also in good agreement with 2.9672 × 10<sup>8</sup> m/s given by the numerical analysis with an uncertainty of 10<sup>−3</sup>. Our demonstration promises a key to hollow-core waveguide characterization for future wide-bandwidth and low-latency optical communication. |
| format | Article |
| id | doaj-art-6159c0f93bf74d6bbfb4eee40de182bc |
| institution | Kabale University |
| issn | 1424-8220 |
| language | English |
| publishDate | 2024-10-01 |
| publisher | MDPI AG |
| record_format | Article |
| series | Sensors |
| spelling | doaj-art-6159c0f93bf74d6bbfb4eee40de182bc2024-11-08T14:41:38ZengMDPI AGSensors1424-82202024-10-012421695410.3390/s24216954Speed of Light in Hollow-Core Photonic Bandgap Fiber Approaching That in VacuumXiaolu Cao0Mingming Luo1Jianfei Liu2Jie Ma3Yundong Hao4Yange Liu5School of Electronic and Information Engineering, Hebei University of Technology, Tianjin 300401, ChinaSchool of Electronic and Information Engineering, Hebei University of Technology, Tianjin 300401, ChinaSchool of Electronic and Information Engineering, Hebei University of Technology, Tianjin 300401, ChinaSchool of Electronic and Information Engineering, Hebei University of Technology, Tianjin 300401, ChinaInstitute of Modern Optics, Nankai University, Tianjin 300350, ChinaInstitute of Modern Optics, Nankai University, Tianjin 300350, ChinaA Fresnel mirror is introduced at a hollow-core photonic bandgap fiber end by fusion splicing a short single-mode fiber segment, to reflect the light backward to an optical frequency domain reflectometry. The backward Fresnel reflection is used as a probe light to achieve light speed measurement with a high resolution and a high signal-to-noise ratio. Thus, its group velocity is obtained with the round-trip time delay as well as the beat frequency at the reflection peak. Multiple Fresnel peaks are observed from 2180.00 Hz to 13,988.75 Hz, corresponding to fusion-spliced hollow-core fiber segments with different lengths from 0.2595 m to 1.6678 m, respectively. The speed of light in the air guidance is calculated at 2.9753 × 10<sup>8</sup> m/s, approaching that in vacuum, which is also in good agreement with 2.9672 × 10<sup>8</sup> m/s given by the numerical analysis with an uncertainty of 10<sup>−3</sup>. Our demonstration promises a key to hollow-core waveguide characterization for future wide-bandwidth and low-latency optical communication.https://www.mdpi.com/1424-8220/24/21/6954hollow-core photonic bandgap fiberFresnel reflectionoptical frequency domain reflectometrylight speed measurement |
| spellingShingle | Xiaolu Cao Mingming Luo Jianfei Liu Jie Ma Yundong Hao Yange Liu Speed of Light in Hollow-Core Photonic Bandgap Fiber Approaching That in Vacuum Sensors hollow-core photonic bandgap fiber Fresnel reflection optical frequency domain reflectometry light speed measurement |
| title | Speed of Light in Hollow-Core Photonic Bandgap Fiber Approaching That in Vacuum |
| title_full | Speed of Light in Hollow-Core Photonic Bandgap Fiber Approaching That in Vacuum |
| title_fullStr | Speed of Light in Hollow-Core Photonic Bandgap Fiber Approaching That in Vacuum |
| title_full_unstemmed | Speed of Light in Hollow-Core Photonic Bandgap Fiber Approaching That in Vacuum |
| title_short | Speed of Light in Hollow-Core Photonic Bandgap Fiber Approaching That in Vacuum |
| title_sort | speed of light in hollow core photonic bandgap fiber approaching that in vacuum |
| topic | hollow-core photonic bandgap fiber Fresnel reflection optical frequency domain reflectometry light speed measurement |
| url | https://www.mdpi.com/1424-8220/24/21/6954 |
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