Pub Date : 2025-11-03DOI: 10.1016/j.yofte.2025.104472
Bin Liu , Zhuo Shan , Lin Yang , Yiqun Wang , Jianyang Hu , Yan Wang , Qiujie Dang , Shuang Xiao , Peng Jin
We propose to use Extrinsic Fabry–Perot Interferometric (EFPI) acoustic sensors to detect heart sound signals in order to eliminate the adverse effects of electromagnetic interference. A fiber-optic EFPI acoustic sensor based on graphene membrane is produced. Its mechanical sensitivity is 760 nm/Pa at 630 Hz. By analyzing the time–frequency domain, we have demonstrated the possibility and effectiveness of using fiber-optic EFPI sensors for heart sound measurement. Mel-Frequency Cepstral Coefficients (MFCCs) extracted from heart sound signals are subsequently put into two deep learning architectures: CNN+GRU and CNN+LSTM , which are utilized for the identification of abnormal heart sounds. Remarkably, these neural networks achieve recognition accuracies of up to 98.65% and 99.51% respectively, highlighting their robust performance in this application.
{"title":"Abnormal heart sound signal recognition based on fiber-optic EFPI sensor","authors":"Bin Liu , Zhuo Shan , Lin Yang , Yiqun Wang , Jianyang Hu , Yan Wang , Qiujie Dang , Shuang Xiao , Peng Jin","doi":"10.1016/j.yofte.2025.104472","DOIUrl":"10.1016/j.yofte.2025.104472","url":null,"abstract":"<div><div>We propose to use Extrinsic Fabry–Perot Interferometric (EFPI) acoustic sensors to detect heart sound signals in order to eliminate the adverse effects of electromagnetic interference. A fiber-optic EFPI acoustic sensor based on graphene membrane is produced. Its mechanical sensitivity is 760 nm/Pa at 630 Hz. By analyzing the time–frequency domain, we have demonstrated the possibility and effectiveness of using fiber-optic EFPI sensors for heart sound measurement. Mel-Frequency Cepstral Coefficients (MFCCs) extracted from heart sound signals are subsequently put into two deep learning architectures: CNN+GRU and CNN+LSTM , which are utilized for the identification of abnormal heart sounds. Remarkably, these neural networks achieve recognition accuracies of up to 98.65% and 99.51% respectively, highlighting their robust performance in this application.</div></div>","PeriodicalId":19663,"journal":{"name":"Optical Fiber Technology","volume":"95 ","pages":"Article 104472"},"PeriodicalIF":2.7,"publicationDate":"2025-11-03","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145465821","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"计算机科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Coherent passive optical networks (PONs) provide a cost-effective point-to-multipoint connection to fixed users. The next-generation PON is envisioned to offer higher data rate, more access points, and flexible coverage. To support these features, we employ power-domain non-orthogonal multiple access (PD-NOMA) with distinct pilot insertion schemes for uplink and downlink transmission. Both theoretical analysis and experimental data confirm that the NOMA system can achieve comparable capacity to the traditional orthogonal multiplexing systems. We experimentally demonstrate the first 200 Gb/s bi-directional NOMA-PON transmission over 20-km standard single-mode fiber (SSMF), achieving power budgets of 41 dB and 35 dB for the strong and weak users in the downlink respectively, and 37 dB in the uplink. These results show the high access flexibility and robustness of PD-NOMA under diverse frequency, phase, polarization, and dispersion conditions, highlighting its potential for high-density 200-G PON applications.
{"title":"200Gbps flexible coherent PD-NOMA PON in uplink and downlink with >35-dB power budget using successive interference cancellation","authors":"Dangui Huang, Yixiao Zhu, Lina Man, Yikun Zhang, Guangying Yang, Gengming Lin, Mengyue Shi, Lilin Yi, Weisheng Hu","doi":"10.1016/j.yofte.2025.104466","DOIUrl":"10.1016/j.yofte.2025.104466","url":null,"abstract":"<div><div>Coherent passive optical networks (PONs) provide a cost-effective point-to-multipoint connection to fixed users. The next-generation PON is envisioned to offer higher data rate, more access points, and flexible coverage. To support these features, we employ power-domain non-orthogonal multiple access (PD-NOMA) with distinct pilot insertion schemes for uplink and downlink transmission. Both theoretical analysis and experimental data confirm that the NOMA system can achieve comparable capacity to the traditional orthogonal multiplexing systems. We experimentally demonstrate the first 200 Gb/s bi-directional NOMA-PON transmission over 20-km standard single-mode fiber (SSMF), achieving power budgets of 41 dB and 35 dB for the strong and weak users in the downlink respectively, and 37 dB in the uplink. These results show the high access flexibility and robustness of PD-NOMA under diverse frequency, phase, polarization, and dispersion conditions, highlighting its potential for high-density 200-G PON applications.</div></div>","PeriodicalId":19663,"journal":{"name":"Optical Fiber Technology","volume":"95 ","pages":"Article 104466"},"PeriodicalIF":2.7,"publicationDate":"2025-11-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145416268","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"计算机科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2025-10-31DOI: 10.1016/j.yofte.2025.104470
Gustavo Sousa Pavani , Dipankar Sengupta , Maria Freire-Hermelo , Antoine Lavignotte , Christine Tremblay , Catherine Lepers
In dynamic optical networks, wavelength-dependent power control is a challenging issue because it can dramatically affect lightpath quality of transmission. To address this issue, the authors proposed a reinforcement learning (RL) channel power equalization method to compensate EDFA wavelength-dependent gain in a single step. The optical power of the active WDM channels is monitored at the endpoints of the optical multiplex section (OMS) to learn the best policy for optimizing the variable attenuation elements of the reconfigurable optical add-drop multiplexer (ROADM). The proposed approach is validated experimentally on a three-span WDM experimental testbed, where a surrogate model of the RL environment significantly reduces the management effort required to collect samples. The applicability of the RL method to our experimental system demonstrates an average power difference reduction up to 87%, which was obtained for the 24-channel random allocation use case.
{"title":"Reinforcement learning-based wavelength-dependent power control for WDM systems","authors":"Gustavo Sousa Pavani , Dipankar Sengupta , Maria Freire-Hermelo , Antoine Lavignotte , Christine Tremblay , Catherine Lepers","doi":"10.1016/j.yofte.2025.104470","DOIUrl":"10.1016/j.yofte.2025.104470","url":null,"abstract":"<div><div>In dynamic optical networks, wavelength-dependent power control is a challenging issue because it can dramatically affect lightpath quality of transmission. To address this issue, the authors proposed a reinforcement learning (RL) channel power equalization method to compensate EDFA wavelength-dependent gain in a single step. The optical power of the active WDM channels is monitored at the endpoints of the optical multiplex section (OMS) to learn the best policy for optimizing the variable attenuation elements of the reconfigurable optical add-drop multiplexer (ROADM). The proposed approach is validated experimentally on a three-span WDM experimental testbed, where a surrogate model of the RL environment significantly reduces the management effort required to collect samples. The applicability of the RL method to our experimental system demonstrates an average power difference reduction up to 87%, which was obtained for the 24-channel random allocation use case.</div></div>","PeriodicalId":19663,"journal":{"name":"Optical Fiber Technology","volume":"95 ","pages":"Article 104470"},"PeriodicalIF":2.7,"publicationDate":"2025-10-31","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145416269","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"计算机科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2025-10-31DOI: 10.1016/j.yofte.2025.104464
Muhammad Fahmi Naqib Nashron , Salmah Karman , Wan Safwani Wan Kamarul Zaman , Rozalina Zakaria , Sharifah Norsyahindah Syed Nor , Sulaiman Wadi Harun
Rapid detection of Salmonella is essential for effective clinical management and control of outbreaks. Traditional culture-based methods, while accurate, are time-consuming and unsuitable for rapid diagnostics. In recent years, surface plasmon resonance (SPR)-based biosensors, especially when integrated with fiber optic technologies, have garnered attention for their sensitivity, label-free detection, and potential for point-of-care applications. Two-dimensional materials such as 2D materials and transition metal dichalcogenides (TMDCs) have recently attracted considerable attention for biosensing applications that significantly enhance sensor sensitivity and performance. This review consolidates recent advances in SPR-based fiber optic biosensors specifically for Salmonella detection. It highlights key sensor configurations, materials, and mechanisms that enhance detection capabilities, along with innovations in sensing elements and integration strategies. The article also compares conventional detection methods with SPR fiber-optic alternatives, evaluates current challenges such as sensitivity limitations, and outlines opportunities for future development in clinical and food safety applications.
{"title":"Incorporation 2D-TMDC for high performance surface plasmon resonance (SPR) based fiber optic biosensor for early Salmonella detection: A review","authors":"Muhammad Fahmi Naqib Nashron , Salmah Karman , Wan Safwani Wan Kamarul Zaman , Rozalina Zakaria , Sharifah Norsyahindah Syed Nor , Sulaiman Wadi Harun","doi":"10.1016/j.yofte.2025.104464","DOIUrl":"10.1016/j.yofte.2025.104464","url":null,"abstract":"<div><div>Rapid detection of <em>Salmonella</em> is essential for effective clinical management and control of outbreaks. Traditional culture-based methods, while accurate, are time-consuming and unsuitable for rapid diagnostics. In recent years, surface plasmon resonance (SPR)-based biosensors, especially when integrated with fiber optic technologies, have garnered attention for their sensitivity, label-free detection, and potential for point-of-care applications. Two-dimensional materials such as 2D materials and transition metal dichalcogenides (TMDCs) have recently attracted considerable attention for biosensing applications that significantly enhance sensor sensitivity and performance. This review consolidates recent advances in SPR-based fiber optic biosensors specifically for <em>Salmonella</em> detection. It highlights key sensor configurations, materials, and mechanisms that enhance detection capabilities, along with innovations in sensing elements and integration strategies. The article also compares conventional detection methods with SPR fiber-optic alternatives, evaluates current challenges such as sensitivity limitations, and outlines opportunities for future development in clinical and food safety applications.</div></div>","PeriodicalId":19663,"journal":{"name":"Optical Fiber Technology","volume":"95 ","pages":"Article 104464"},"PeriodicalIF":2.7,"publicationDate":"2025-10-31","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145416271","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"计算机科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2025-10-31DOI: 10.1016/j.yofte.2025.104463
Hanlin Liu , Yongfeng Zou , Peng Chen , Shuyuan Guo , Miao Liu , Jingru Mao , Dandan Sun , Jie Ma
This article employs Brillouin optical time domain reflection (BOTDR) technology for the long-term monitoring of backfill slopes in open-pit coal mines, utilizing a 300-meter optical cable. By analyzing the monitoring data, the primary factors influencing the stress changes in the backfill slopes are identified, with a major impact of rainfall effect. During rainfall events, the minimum frequency within the 300-meter stretch of the backfill slope increased from 91.1 Hz to 122.3 Hz, showing a variation of 31.2 Hz. Similarly, the maximum frequency change rose from 221.5 Hz to 452.2 Hz, with a variation of 230.7 Hz. The use of specially armored optical cables in the BOTDR system demonstrates excellent real-time performance, enabling precise monitoring of stress changes and providing strong support for slope stability assessment and landslide early warning. This technology offers a viable solution for long-distance slope monitoring in open-pit coal mines and similar projects.
{"title":"Real-time stress monitoring of backfill slopes in open-pit coal mines using Brillouin optical time domain reflectometry technology","authors":"Hanlin Liu , Yongfeng Zou , Peng Chen , Shuyuan Guo , Miao Liu , Jingru Mao , Dandan Sun , Jie Ma","doi":"10.1016/j.yofte.2025.104463","DOIUrl":"10.1016/j.yofte.2025.104463","url":null,"abstract":"<div><div>This article employs Brillouin optical time domain reflection (BOTDR) technology for the long-term monitoring of backfill slopes in open-pit coal mines, utilizing a 300-meter optical cable. By analyzing the monitoring data, the primary factors influencing the stress changes in the backfill slopes are identified, with a major impact of rainfall effect. During rainfall events, the minimum frequency within the 300-meter stretch of the backfill slope increased from 91.1 Hz to 122.3 Hz, showing a variation of 31.2 Hz. Similarly, the maximum frequency change rose from 221.5 Hz to 452.2 Hz, with a variation of 230.7 Hz. The use of specially armored optical cables in the BOTDR system demonstrates excellent real-time performance, enabling precise monitoring of stress changes and providing strong support for slope stability assessment and landslide early warning. This technology offers a viable solution for long-distance slope monitoring in open-pit coal mines and similar projects.</div></div>","PeriodicalId":19663,"journal":{"name":"Optical Fiber Technology","volume":"95 ","pages":"Article 104463"},"PeriodicalIF":2.7,"publicationDate":"2025-10-31","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145416272","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"计算机科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2025-10-31DOI: 10.1016/j.yofte.2025.104469
Arturo Gaviria-Calderón, Brayan Patiño-Jurado, Juan F. Botero-Cadavid, Jorge Garcia-Sucerquia
In this work, the design, construction and testing of a cost-effective, portable, and 3D-printed sensing platform based on optical fiber for rapid detection of mercury (II) ions in water is presented. The core of the platform is a highly reproducible sensor based on an etched single-mode–multimode–single-mode (E-SMS) optical fiber structure; it is fabricated by chemical etching and activated with a nanostructured chitosan/Maghemite (CS/γFe2O3) composite thin film for the selective detection of mercury ions (Hg2+) in water. The optical fiber structure is interrogated with an affordable home-made spectrometer and a digital processing system to experimentally verify its capability for optical detection of Hg2+ in water; the platform exhibits a wavelength-modulated response with sensitivity of 3.9 nm/(µg/mL) and provides the ability to selectively detect low concentrations of up to 1 ng/mL (one part per billion) of Hg2+ in laboratory-prepared water samples. The proposed architecture, which can be built from scratch by approximately $160, is constructed using a 3D-printed setup and off-the-shelf materials. This approach enables the creation of a cost-effective, simple-to-manufacture, and portable sensing platform, which shows promise for on-site detection and monitoring of mercury contamination in water sources.
{"title":"Cost-effective, portable, and 3D-printed sensing platform for selective measuring of toxic mercury (II) ions in water","authors":"Arturo Gaviria-Calderón, Brayan Patiño-Jurado, Juan F. Botero-Cadavid, Jorge Garcia-Sucerquia","doi":"10.1016/j.yofte.2025.104469","DOIUrl":"10.1016/j.yofte.2025.104469","url":null,"abstract":"<div><div>In this work, the design, construction and testing of a cost-effective, portable, and 3D-printed sensing platform based on optical fiber for rapid detection of mercury (II) ions in water is presented. The core of the platform is a highly reproducible sensor based on an etched single-mode–multimode–single-mode (E-SMS) optical fiber structure; it is fabricated by chemical etching and activated with a nanostructured chitosan/Maghemite (CS/γFe<sub>2</sub>O<sub>3</sub>) composite thin film for the selective detection of mercury ions (Hg<sup>2+</sup>) in water. The optical fiber structure is interrogated with an affordable home-made spectrometer and a digital processing system to experimentally verify its capability for optical detection of Hg<sup>2+</sup> in water; the platform exhibits a wavelength-modulated response with sensitivity of 3.9 nm/(µg/mL) and provides the ability to selectively detect low concentrations of up to 1 ng/mL (one part per billion) of Hg<sup>2+</sup> in laboratory-prepared water samples. The proposed architecture, which can be built from scratch by approximately $160, is constructed using a 3D-printed setup and off-the-shelf materials. This approach enables the creation of a cost-effective, simple-to-manufacture, and portable sensing platform, which shows promise for on-site detection and monitoring of mercury contamination in water sources.</div></div>","PeriodicalId":19663,"journal":{"name":"Optical Fiber Technology","volume":"95 ","pages":"Article 104469"},"PeriodicalIF":2.7,"publicationDate":"2025-10-31","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145416270","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"计算机科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2025-10-28DOI: 10.1016/j.yofte.2025.104459
Zhipeng Ding , Di Xin , Xinyu Liu , Zhenjiao Shan , Xuyan Zhou , Hongbo Zhang , Wanhua Zheng
We report an all-polarization-maintaining (PM) nonlinear amplifying loop mirror (NALM) mode-locked erbium-doped fiber laser at 1565 nm. With all other cavity parameters fixed, tuning only the pump power enables reversible switching between pure noise-like pulses (NLPs) and bound-state NLPs. In the NLP regime the output shows a 9.6 ps pedestal and a 140 fs spike with a 55 nm optical bandwidth, yielding an effective width shorter than previously reported NLP source; the repetition rate is 27.80 MHz and the maximum average power is 13.55 mW. In the bound-state regime a 0.34 nm spectral-modulation period indicates a 24 ps inter-packet separation. Numerical simulations reproduce both regimes and attribute the NLP-to-bound-state transition to the combined roles of intensity-dependent NALM interference in an anti-saturation region and alternating dispersion. These results broaden the nonlinear-dynamics landscape of PM-NALM fiber lasers and provide a robust broadband-source route for supercontinuum generation and low-coherence imaging.
{"title":"Interconversion between Noise-Like pulses and Bound-State Noise-Like pulses in NALM Mode-Locked fiber laser","authors":"Zhipeng Ding , Di Xin , Xinyu Liu , Zhenjiao Shan , Xuyan Zhou , Hongbo Zhang , Wanhua Zheng","doi":"10.1016/j.yofte.2025.104459","DOIUrl":"10.1016/j.yofte.2025.104459","url":null,"abstract":"<div><div>We report an all-polarization-maintaining (PM) nonlinear amplifying loop mirror (NALM) mode-locked erbium-doped fiber laser at 1565 nm. With all other cavity parameters fixed, tuning only the pump power enables reversible switching between pure noise-like pulses (NLPs) and bound-state NLPs. In the NLP regime the output shows a 9.6 ps pedestal and a 140 fs spike with a 55 nm optical bandwidth, yielding an effective width shorter than previously reported NLP source; the repetition rate is 27.80 MHz and the maximum average power is 13.55 mW. In the bound-state regime a 0.34 nm spectral-modulation period indicates a 24 ps inter-packet separation. Numerical simulations reproduce both regimes and attribute the NLP-to-bound-state transition to the combined roles of intensity-dependent NALM interference in an anti-saturation region and alternating dispersion. These results broaden the nonlinear-dynamics landscape of PM-NALM fiber lasers and provide a robust broadband-source route for supercontinuum generation and low-coherence imaging.</div></div>","PeriodicalId":19663,"journal":{"name":"Optical Fiber Technology","volume":"95 ","pages":"Article 104459"},"PeriodicalIF":2.7,"publicationDate":"2025-10-28","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145416273","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"计算机科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
This study optimizes a dual-core fiber (DCF) design for femtosecond nonlinear dual-wavelength switching applications at 1030 nm (control pulse, CP) and 2000 nm (signal pulse, SP). Building on prior works in the C-band, we address CP-SP temporal synchronization, fabrication challenges, and functional enhancements. The DCF composes lead-silicate PBG-08 glass for the cores and borosilicate UV-710 glass for the cladding, for the purpose of high refractive index contrast, strong nonlinear interaction, and extended transmission beyond the near infrared. Core diameter (2.4 μm) and spacing (3.9 μm) were tuned for improved dispersion, coupling, and synchronization within a compact 1 cm length. We developed a novel fabrication approach to maintain circular core shapes and minimize asymmetry, improving consistency and applicability of previous DCF designs. We analyzed effects of ±0.2 μm core ellipticity, finding minimal impact on group velocity and coupling length. The key importance characteristics of the optimized design promises higher switching contrast, reduced signal pulse distortions and extended wavelength range toward the mid-infrared. These predictions enhance the application potential of the analyzed specialty DCF in telecommunications, imaging, and sensing applications.
{"title":"All-solid dual-core fiber design for dual-wavelength 1–2 µm control-signal switching of ultrafast pulses","authors":"Mattia Longobucco , Dariusz Pysz , Ryszard Buczyński , Ignác Bugár","doi":"10.1016/j.yofte.2025.104449","DOIUrl":"10.1016/j.yofte.2025.104449","url":null,"abstract":"<div><div>This study optimizes a dual-core fiber (DCF) design for femtosecond nonlinear dual-wavelength switching applications at 1030 nm (control pulse, CP) and 2000 nm (signal pulse, SP). Building on prior works in the C-band, we address CP-SP temporal synchronization, fabrication challenges, and functional enhancements. The DCF composes lead-silicate PBG-08 glass for the cores and borosilicate UV-710 glass for the cladding, for the purpose of high refractive index contrast, strong nonlinear interaction, and extended transmission beyond the near infrared. Core diameter (2.4 μm) and spacing (3.9 μm) were tuned for improved dispersion, coupling, and synchronization within a compact 1 cm length. We developed a novel fabrication approach to maintain circular core shapes and minimize asymmetry, improving consistency and applicability of previous DCF designs. We analyzed effects of ±0.2 μm core ellipticity, finding minimal impact on group velocity and coupling length. The key importance characteristics of the optimized design promises higher switching contrast, reduced signal pulse distortions and extended wavelength range toward the mid-infrared. These predictions enhance the application potential of the analyzed specialty DCF in telecommunications, imaging, and sensing applications.</div></div>","PeriodicalId":19663,"journal":{"name":"Optical Fiber Technology","volume":"95 ","pages":"Article 104449"},"PeriodicalIF":2.7,"publicationDate":"2025-10-25","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145362989","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"计算机科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Stimulated emission depletion microscopy (STED) can break through diffraction limit to achieve super-resolution imaging, and it is currently applied in the forefront of biomedical and other fields. In this work, a super-resolution tight focusing theoretical model of STED beam generated by optical fiber is established based on far-field diffraction and Richards-Wolf vector diffraction theory. The tight focusing characteristics of different mode representations in optical fiber are researched systematically. Meanwhile, the effects of different modes on resolution of STED imaging system are revealed. Here, it is reported that low-order vector TE01 mode and orbital angular momentum (OAM) mode with topological charge number l of ±1 after being focused by a high NA objective lens, produces a ring-shaped depletion beam with good quality. The full width at half maximum (FWHM) of TE01 mode at radial light intensity is approximately 440 nm, and the achievable imaging system resolution is about 54 nm at visible wavelength. These results provide theoretical guidance for building super-resolution imaging systems with optical devices.
{"title":"Super-resolution focusing performance of different modes in optical fiber based on vector diffraction far-field","authors":"Xiaojie Guo , Boyi Yang , Yinghao Guo , Guobin Ren","doi":"10.1016/j.yofte.2025.104453","DOIUrl":"10.1016/j.yofte.2025.104453","url":null,"abstract":"<div><div>Stimulated emission depletion microscopy (STED) can break through diffraction limit to achieve super-resolution imaging, and it is currently applied in the forefront of biomedical and other fields. In this work, a super-resolution tight focusing theoretical model of STED beam generated by optical fiber is established based on far-field diffraction and Richards-Wolf vector diffraction theory. The tight focusing characteristics of different mode representations in optical fiber are researched systematically. Meanwhile, the effects of different modes on resolution of STED imaging system are revealed. Here, it is reported that low-order vector TE<sub>01</sub> mode and orbital angular momentum (OAM) mode with topological charge number <em>l</em> of ±1 after being focused by a high NA objective lens, produces a ring-shaped depletion beam with good quality. The full width at half maximum (FWHM) of TE<sub>01</sub> mode at radial light intensity is approximately 440 nm, and the achievable imaging system resolution is about 54 nm at visible wavelength. These results provide theoretical guidance for building super-resolution imaging systems with optical devices.</div></div>","PeriodicalId":19663,"journal":{"name":"Optical Fiber Technology","volume":"95 ","pages":"Article 104453"},"PeriodicalIF":2.7,"publicationDate":"2025-10-25","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145362988","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"计算机科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2025-10-25DOI: 10.1016/j.yofte.2025.104457
Andrei V. Shirmankin , Vladimir A. Kamynin , Andrei D. Zverev , Denis A. Guryev , Yuriy G. Gladush , Dmitry V. Krasnikov , Albert G. Nasibulin , Vladimir B. Tsvetkov
We have demonstrated a tunable erbium-doped ring fiber laser using an intracavity optical filter based on a tapered fiber. By adjusting the optical filter, we were able to tune the laser’s central wavelength. The tapered fiber was created from a commercially available single-mode optical fiber using the Vytran GPX 3400 setup. Thin films of aerosol CVD-synthesized single-walled carbon nanotubes were used to achieve mode locking with a pulse duration of up to 1 picosecond. We compared three tapered fibers with different waist diameters and demonstrated continuous tuning of the laser wavelength over a range of 8.5 nm while maintaining stable mode locking.
{"title":"Tunable erbium laser with intracavity optical filter based on tapered fiber","authors":"Andrei V. Shirmankin , Vladimir A. Kamynin , Andrei D. Zverev , Denis A. Guryev , Yuriy G. Gladush , Dmitry V. Krasnikov , Albert G. Nasibulin , Vladimir B. Tsvetkov","doi":"10.1016/j.yofte.2025.104457","DOIUrl":"10.1016/j.yofte.2025.104457","url":null,"abstract":"<div><div>We have demonstrated a tunable erbium-doped ring fiber laser using an intracavity optical filter based on a tapered fiber. By adjusting the optical filter, we were able to tune the laser’s central wavelength. The tapered fiber was created from a commercially available single-mode optical fiber using the Vytran GPX 3400 setup. Thin films of aerosol CVD-synthesized single-walled carbon nanotubes were used to achieve mode locking with a pulse duration of up to 1 picosecond. We compared three tapered fibers with different waist diameters and demonstrated continuous tuning of the laser wavelength over a range of 8.5 nm while maintaining stable mode locking.</div></div>","PeriodicalId":19663,"journal":{"name":"Optical Fiber Technology","volume":"95 ","pages":"Article 104457"},"PeriodicalIF":2.7,"publicationDate":"2025-10-25","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145362987","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"计算机科学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
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