Pub Date : 2026-05-01Epub Date: 2026-01-24DOI: 10.1016/j.yofte.2026.104565
Alexander Sudin , Igor Volkov , Sergey Ushakov , Konstantin Nishchev
We report an experimental study of an Er/Yb-doped fiber ring laser with a cavity length exceeding 300 m, mode locked through nonlinear polarization evolution. By adjusting the orientation of the polarization controllers and the pump power, we generated noise-like pulses exhibiting a period-doubling bifurcation. The pulse bunches had a trapezoidal shape, with different amplitudes and widths on even and odd cavity roundtrips. It was shown that the bunch widths were proportional to the change in pump power. The maximum bunch widths were 10.2 ns and 5.2 ns for even and odd cavity roundtrips, respectively.
{"title":"Period-doubling bifurcation of noise-like pulses in a passively mode-locked fiber laser","authors":"Alexander Sudin , Igor Volkov , Sergey Ushakov , Konstantin Nishchev","doi":"10.1016/j.yofte.2026.104565","DOIUrl":"10.1016/j.yofte.2026.104565","url":null,"abstract":"<div><div>We report an experimental study of an Er/Yb-doped fiber ring laser with a cavity length exceeding 300 m, mode locked through nonlinear polarization evolution. By adjusting the orientation of the polarization controllers and the pump power, we generated noise-like pulses exhibiting a period-doubling bifurcation. The pulse bunches had a trapezoidal shape, with different amplitudes and widths on even and odd cavity roundtrips. It was shown that the bunch widths were proportional to the change in pump power. The maximum bunch widths were 10.2 ns and 5.2 ns for even and odd cavity roundtrips, respectively.</div></div>","PeriodicalId":19663,"journal":{"name":"Optical Fiber Technology","volume":"98 ","pages":"Article 104565"},"PeriodicalIF":2.7,"publicationDate":"2026-05-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"146078273","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 : 2026-05-01Epub Date: 2025-12-21DOI: 10.1016/j.yofte.2025.104517
Supu Xiu , Shuangshuang Han , Ying Zhang , Fang Wang , Xinyi Zhao , Yufang Liu
To investigate the effect of tapering position on the temperature detection sensitivity of single mode fiber–dispersion compensated fiber–single mode fiber (SDS) sensors, this paper fabricated four Mach-Zehnder Interferometer (MZI) fiber sensors based on dispersion-compensated fiber (DCF): the SDS fiber sensor, the SDS fiber sensor with tapering on single-mode fiber (STDS), the SDS sensor with tapering on DCF(SDTS), and the SDS sensor with tapering on both SMF and DCF (STDTS). Their temperature sensitivities are tested within the range of 30–300 °C. The results show that the sensitivities of the four sensors are 48.68 pm/°C, 51.04 pm/°C, 104.17 pm/°C, and 108.36 pm/°C, respectively. Notably, the STDTS fiber sensor exhibits approximately 2.2 times higher sensitivity than the SDS. Additionally, the optimization effect of tapering on DCF is significantly better than that on SMF. This indicates that tapering position is a key and effective factor in regulating the temperature measurement sensitivity of SDS fiber sensors, and reasonable design of the tapering position can greatly enhance their temperature measurement performance.
{"title":"The critical role of tapering position on the sensitivity of SDS fiber sensor for temperature detection","authors":"Supu Xiu , Shuangshuang Han , Ying Zhang , Fang Wang , Xinyi Zhao , Yufang Liu","doi":"10.1016/j.yofte.2025.104517","DOIUrl":"10.1016/j.yofte.2025.104517","url":null,"abstract":"<div><div>To investigate the effect of tapering position on the temperature detection sensitivity of single mode fiber–dispersion compensated fiber–single mode fiber (SDS) sensors, this paper fabricated four Mach-Zehnder Interferometer (MZI) fiber sensors based on dispersion-compensated fiber (DCF): the SDS fiber sensor, the SDS fiber sensor with tapering on single-mode fiber (STDS), the SDS sensor with tapering on DCF(SDTS), and the SDS sensor with tapering on both SMF and DCF (STDTS). Their temperature sensitivities are tested within the range of 30–300 °C. The results show that the sensitivities of the four sensors are 48.68 pm/°C, 51.04 pm/°C, 104.17 pm/°C, and 108.36 pm/°C, respectively. Notably, the STDTS fiber sensor exhibits approximately 2.2 times higher sensitivity than the SDS. Additionally, the optimization effect of tapering on DCF is significantly better than that on SMF. This indicates that tapering position is a key and effective factor in regulating the temperature measurement sensitivity of SDS fiber sensors, and reasonable design of the tapering position can greatly enhance their temperature measurement performance.</div></div>","PeriodicalId":19663,"journal":{"name":"Optical Fiber Technology","volume":"98 ","pages":"Article 104517"},"PeriodicalIF":2.7,"publicationDate":"2026-05-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145841860","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 : 2026-05-01Epub Date: 2025-12-31DOI: 10.1016/j.yofte.2025.104547
Li Zhao , Jianyu Long , Jianjun Yu
O-band IM/DD systems offer a cost-efficient solution for high-speed data center interconnects (DCIs) spanning tens of kilometers without additional dispersion management. Yet, sampling frequency offset (SFO) resulting from DAC and ADC sampling rate mismatches significantly challenges PAM signals. Conventional methods like Gardner interpolation, which rely on neighboring samples, have limited SFO correction capabilities. Moreover, Gardner’s approach may obscure SFO effects in PAM signals, often misleadingly attributed solely to the sampling phase of timing recovery issues, with scant research dedicated to the underlying SFO analysis and compensation in PAM systems. In this work, we analyze SFO-induced inter-symbol interference (ISI) and demonstrate how it disrupts digital equalizers and universal clock recovery algorithms like Gardner’s method for PAM signals. We propose a digital interpolation-based SFO compensation method for O-band IM/DD PAM-4 systems over a 40-km SSMF link. Experimental results show that the proposed method improves BER performance, ensuring stable operation for long signal frames where SFO leads to significant errors.
o波段IM/DD系统为跨越数十公里的高速数据中心互连（dci）提供了一种经济高效的解决方案，而无需额外的分散管理。然而，由DAC和ADC采样率不匹配引起的采样频率偏移（SFO）严重挑战了PAM信号。Gardner插值等传统方法依赖于邻近样本，SFO校正能力有限。此外，Gardner的方法可能会模糊PAM信号中的SFO效应，通常会将其错误地仅仅归因于定时恢复问题的采样阶段，而对PAM系统中潜在的SFO分析和补偿的研究很少。在这项工作中，我们分析了sfo引起的符号间干扰（ISI），并演示了它如何破坏数字均衡器和通用时钟恢复算法，如PAM信号的Gardner方法。针对40 km SSMF链路上的o波段IM/DD PAM-4系统，提出了一种基于数字插值的SFO补偿方法。实验结果表明，该方法提高了误码率，保证了SFO误差较大的长信号帧的稳定运行。
{"title":"Sampling frequency offset in IM/DD DCI Systems: Analysis and compensation for PAM signals","authors":"Li Zhao , Jianyu Long , Jianjun Yu","doi":"10.1016/j.yofte.2025.104547","DOIUrl":"10.1016/j.yofte.2025.104547","url":null,"abstract":"<div><div>O-band IM/DD systems offer a cost-efficient solution for high-speed data center interconnects (DCIs) spanning tens of kilometers without additional dispersion management. Yet, sampling frequency offset (SFO) resulting from DAC and ADC sampling rate mismatches significantly challenges PAM signals. Conventional methods like Gardner interpolation, which rely on neighboring samples, have limited SFO correction capabilities. Moreover, Gardner’s approach may obscure SFO effects in PAM signals, often misleadingly attributed solely to the sampling phase of timing recovery issues, with scant research dedicated to the underlying SFO analysis and compensation in PAM systems. In this work, we analyze SFO-induced inter-symbol interference (ISI) and demonstrate how it disrupts digital equalizers and universal clock recovery algorithms like Gardner’s method for PAM signals. We propose a digital interpolation-based SFO compensation method for O-band IM/DD PAM-4 systems over a 40-km SSMF link. Experimental results show that the proposed method improves BER performance, ensuring stable operation for long signal frames where SFO leads to significant errors.</div></div>","PeriodicalId":19663,"journal":{"name":"Optical Fiber Technology","volume":"98 ","pages":"Article 104547"},"PeriodicalIF":2.7,"publicationDate":"2026-05-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145885422","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 : 2026-05-01Epub Date: 2026-01-03DOI: 10.1016/j.yofte.2025.104545
Sourav Dutta , Dibbendu Roy , Moyukh Laha , Goutam Das
The 3rd Generation Partnership Project (3GPP) has recognized eXtended Reality (XR) as a key use case for 5G and beyond. However, supporting XR services over such networks is challenging due to their stringent latency, reliability, and data rate requirements. Conventional Dynamic Bandwidth Allocation (DBA) protocols in Ethernet Passive Optical Networks (EPONs) fail to efficiently support the stringent delay-reliability requirements of data-intensive, bursty XR traffic, resulting in poor network utilization. To overcome these limitations, this paper proposes an application-aware cross-layer scheduling philosophy that links Media Access Control (MAC)-layer bandwidth allocation with application-layer dynamics. From the application perspective, variations in XR frame content arise from human activity, making consecutive frames highly correlated. Exploiting this correlation, the proposed “Application-aware MAC” scheduling framework employs AI-based frame prediction at the edge server to enhance delay reliability. To minimize prediction error, the original inter-arrival pattern of XR frames must be preserved. However, EPON scheduling introduces differential delays that distort this pattern. To address this, a novel MAC scheduling scheme is designed that coordinates with play-off buffers at the edge server to manage these differential delays and reconstruct the original inter-arrival pattern, thereby enabling accurate prediction and delay-reliable transmission. Simulation results show that the proposed method achieves up to a ten-fold improvement in XR user supportability compared to the DiffServ approach and about a three-fold gain over a Greedy Earliest-Deadline-First scheduler for a data rate and frame rate of 60 Mbps and 60 fps, respectively, with only negligible prediction error at the application layer.
{"title":"Application-aware MAC scheduling for XR over EPON-based 6G-backhaul","authors":"Sourav Dutta , Dibbendu Roy , Moyukh Laha , Goutam Das","doi":"10.1016/j.yofte.2025.104545","DOIUrl":"10.1016/j.yofte.2025.104545","url":null,"abstract":"<div><div>The 3rd Generation Partnership Project (3GPP) has recognized eXtended Reality (XR) as a key use case for 5G and beyond. However, supporting XR services over such networks is challenging due to their stringent latency, reliability, and data rate requirements. Conventional Dynamic Bandwidth Allocation (DBA) protocols in Ethernet Passive Optical Networks (EPONs) fail to efficiently support the stringent delay-reliability requirements of data-intensive, bursty XR traffic, resulting in poor network utilization. To overcome these limitations, this paper proposes an application-aware cross-layer scheduling philosophy that links Media Access Control (MAC)-layer bandwidth allocation with application-layer dynamics. From the application perspective, variations in XR frame content arise from human activity, making consecutive frames highly correlated. Exploiting this correlation, the proposed “Application-aware MAC” scheduling framework employs AI-based frame prediction at the edge server to enhance delay reliability. To minimize prediction error, the original inter-arrival pattern of XR frames must be preserved. However, EPON scheduling introduces differential delays that distort this pattern. To address this, a novel MAC scheduling scheme is designed that coordinates with play-off buffers at the edge server to manage these differential delays and reconstruct the original inter-arrival pattern, thereby enabling accurate prediction and delay-reliable transmission. Simulation results show that the proposed method achieves up to a ten-fold improvement in XR user supportability compared to the DiffServ approach and about a three-fold gain over a Greedy Earliest-Deadline-First scheduler for a data rate and frame rate of 60 Mbps and 60 fps, respectively, with only negligible prediction error at the application layer.</div></div>","PeriodicalId":19663,"journal":{"name":"Optical Fiber Technology","volume":"98 ","pages":"Article 104545"},"PeriodicalIF":2.7,"publicationDate":"2026-05-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145885514","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 : 2026-05-01Epub Date: 2025-12-23DOI: 10.1016/j.yofte.2025.104528
Wenfeng Luo , Tingting Zhang , Xiaohui Li , Shuyuan Lv , Yerou Wang , Yumeng Cao
Two-dimensional heterostructured materials have gained more and more attention in the field of ultrafast nonlinear optics due to their unique physicochemical properties. In this paper, CNT/In2Se3 heterostructures were successfully prepared by drop-coating In2Se3 dispersions onto the surface of carbon nanotube-polyvinyl alcohol composite films. The modulation depth and loss of this heterostructure were 6.3 % and 26.5 %, respectively, as measured by a double-balance device. Three mode-locked states, i.e., a conventional soliton with a pulse width of 1.71 ps, a 2nd-order with a repetition frequency of 11.9 MHz, and a 13th-order harmonic soliton with a repetition frequency of 77.35 MHz, were realised by integrating it as a saturable absorber in a fibre-optic resonant cavity. These findings indicate that CNT/In2Se3 heterostructures show significant potential for applications in ultrafast nonlinear optical materials.
{"title":"Passively mode-locked fibre laser based on CNT/In2Se3 heterostructure","authors":"Wenfeng Luo , Tingting Zhang , Xiaohui Li , Shuyuan Lv , Yerou Wang , Yumeng Cao","doi":"10.1016/j.yofte.2025.104528","DOIUrl":"10.1016/j.yofte.2025.104528","url":null,"abstract":"<div><div>Two-dimensional heterostructured materials have gained more and more attention in the field of ultrafast nonlinear optics due to their unique physicochemical properties. In this paper, CNT/In<sub>2</sub>Se<sub>3</sub> heterostructures were successfully prepared by drop-coating In<sub>2</sub>Se<sub>3</sub> dispersions onto the surface of carbon nanotube-polyvinyl alcohol composite films. The modulation depth and loss of this heterostructure were 6.3 % and 26.5 %, respectively, as measured by a double-balance device. Three mode-locked states, i.e., a conventional soliton with a pulse width of 1.71 ps, a 2nd-order with a repetition frequency of 11.9 MHz, and a 13th-order harmonic soliton with a repetition frequency of 77.35 MHz, were realised by integrating it as a saturable absorber in a fibre-optic resonant cavity. These findings indicate that CNT/In<sub>2</sub>Se<sub>3</sub> heterostructures show significant potential for applications in ultrafast nonlinear optical materials.</div></div>","PeriodicalId":19663,"journal":{"name":"Optical Fiber Technology","volume":"98 ","pages":"Article 104528"},"PeriodicalIF":2.7,"publicationDate":"2026-05-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145841862","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 : 2026-05-01Epub Date: 2026-01-13DOI: 10.1016/j.yofte.2026.104560
Wenjie Nie , Kai Zhang , Yanhong Li , Zhangwei Yu , Zhengtian Gu , Qiang Ling , Daru Chen
As a critical physiological parameter in health assessment, respiratory offers essential insights into the pathogenesis and progression of cardiovascular disorders, serving as a non-invasive biomarker for disease screening and therapeutic monitoring. In this paper, a high-sensitivity, low-cost optical fiber respiratory measurement system based on a polyvinyl alcohol (PVA) film-coated Fabry-Perot interferometer (FPI) has been presented. The measurement system operates by detecting humidity-induced changes in the PVA film’s refractive index, which modulates the FPI’s interference spectrum. The experimental results demonstrate a linear humidity response with a sensitivity of 59 pm/%RH in the 30–90 %RH, which is suitable for monitoring human respiration. The breath measurement system has been built based on the response characteristics to environmental humidity and an oscilloscope has been used to detect the intensity information at 1550 nm in real time and analyze the respiratory rate. The validation tests successfully captured various breathing patterns, including different frequencies, postures, and prolonged respiration which show good stability and practicality. This sensor demonstrates excellent response time and recovery time of 0.82 s and 0.89 s. The sensor’s compact design, high repeatability, and fast response make it ideal for clinical and home-based respiratory monitoring. This work provides a practical, non-invasive solution for respiratory monitoring, with potential applications in sleep apnea detection, pulmonary rehabilitation, and intensive care.
{"title":"Fiber optic respiratory monitoring: A novel approach for real-time breath analysis","authors":"Wenjie Nie , Kai Zhang , Yanhong Li , Zhangwei Yu , Zhengtian Gu , Qiang Ling , Daru Chen","doi":"10.1016/j.yofte.2026.104560","DOIUrl":"10.1016/j.yofte.2026.104560","url":null,"abstract":"<div><div>As a critical physiological parameter in health assessment, respiratory offers essential insights into the pathogenesis and progression of cardiovascular disorders, serving as a non-invasive biomarker for disease screening and therapeutic monitoring. In this paper, a high-sensitivity, low-cost optical fiber respiratory measurement system based on a polyvinyl alcohol (PVA) film-coated Fabry-Perot interferometer (FPI) has been presented. The measurement system operates by detecting humidity-induced changes in the PVA film’s refractive index, which modulates the FPI’s interference spectrum. The experimental results demonstrate a linear humidity response with a sensitivity of 59 pm/%RH in the 30–90 %RH, which is suitable for monitoring human respiration. The breath measurement system has been built based on the response characteristics to environmental humidity and an oscilloscope has been used to detect the intensity information at 1550 nm in real time and analyze the respiratory rate. The validation tests successfully captured various breathing patterns, including different frequencies, postures, and prolonged respiration which show good stability and practicality. This sensor demonstrates excellent response time and recovery time of 0.82 s and 0.89 s. The sensor’s compact design, high repeatability, and fast response make it ideal for clinical and home-based respiratory monitoring. This work provides a practical, non-invasive solution for respiratory monitoring, with potential applications in sleep apnea detection, pulmonary rehabilitation, and intensive care.</div></div>","PeriodicalId":19663,"journal":{"name":"Optical Fiber Technology","volume":"98 ","pages":"Article 104560"},"PeriodicalIF":2.7,"publicationDate":"2026-05-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145978150","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 : 2026-05-01Epub Date: 2026-01-19DOI: 10.1016/j.yofte.2026.104562
Xiang He , Chuan Peng , Jianzhong Zhang , Zhipeng Lei , Zhe Ma , Tingyu Wang , Mingjiang Zhang
In this paper, a phase-sensitive optical time domain reflectometer (φ-OTDR) based on 3 × 3 coupler phase demodulation is utilized to measure partial discharge (PD) and analyze its discharge characteristics. This paper measures surface and corona discharge at four voltage levels and uses the Michelson interferometer combined with the Arctan demodulation algorithm to demodulate PD signals. The experimental results show that the φ-OTDR method is consistent with the standard pulsed current method regarding the time-domain signal, phase information, discharge intensity, and the number of discharges for surface and corona discharges, which fully demonstrates the PD measurement accuracy of the φ-OTDR method. Frequency spectrum analysis indicates that surface discharge signals are primarily distributed between 37 kHz and 42 kHz, whereas corona discharge signals are concentrated around 30 kHz. Moreover, the φ-OTDR method successfully achieved distributed measurement and localization of the surface and corona discharges, with a localization error of 2 m.
{"title":"Analysis of partial discharge using φ-OTDR based on 3 × 3 coupler phase demodulation","authors":"Xiang He , Chuan Peng , Jianzhong Zhang , Zhipeng Lei , Zhe Ma , Tingyu Wang , Mingjiang Zhang","doi":"10.1016/j.yofte.2026.104562","DOIUrl":"10.1016/j.yofte.2026.104562","url":null,"abstract":"<div><div>In this paper, a phase-sensitive optical time domain reflectometer (φ-OTDR) based on 3 × 3 coupler phase demodulation is utilized to measure partial discharge (PD) and analyze its discharge characteristics. This paper measures surface and corona discharge at four voltage levels and uses the Michelson interferometer combined with the Arctan demodulation algorithm to demodulate PD signals. The experimental results show that the φ-OTDR method is consistent with the standard pulsed current method regarding the time-domain signal, phase information, discharge intensity, and the number of discharges for surface and corona discharges, which fully demonstrates the PD measurement accuracy of the φ-OTDR method. Frequency spectrum analysis indicates that surface discharge signals are primarily distributed between 37 kHz and 42 kHz, whereas corona discharge signals are concentrated around 30 kHz. Moreover, the φ-OTDR method successfully achieved distributed measurement and localization of the surface and corona discharges, with a localization error of 2 m.</div></div>","PeriodicalId":19663,"journal":{"name":"Optical Fiber Technology","volume":"98 ","pages":"Article 104562"},"PeriodicalIF":2.7,"publicationDate":"2026-05-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"146023602","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 : 2026-05-01Epub Date: 2026-01-03DOI: 10.1016/j.yofte.2025.104548
Yanxia Chen , Fengyuan Chen , Xinhong Huang , Yantai Liang , Shuangqiang Liu , Le Luo
The present study puts forward an optical fiber sensor utilizing the Fabry-Perot interferometer (FPI) for simultaneous temperature and salinity measurement, which adopts a dual-cavity structure integrated within a single tube. Functional partitioning design resolves temperature-salinity crosstalk issues. The sensor employs a quartz capillary tube (SCT) to construct a cascaded structure comprising a UV-cured resin cavity (FPI1) and a polyimide-coated gas cavity (FPI2). It leverages the thermal expansion effect of the UV-cured resin and the salt-induced swelling effect of polyimide to realize measuring temperature and salinity simultaneously. Through finite element analysis, the polyimide film thickness and cavity length are optimized to minimize temperature-salinity crosstalk while balancing salinity sensitivity and response time, yielding optimal response characteristics: FPI1 exhibits sensitivity of 0.77 nm/°C for temperature and 0.078 nm/% for salinity, while FPI2 exhibited sensitivities of −0.038 nm/°C and −0.25 nm/%. To validate the theoretical analysis, experimental testing of the temperature-salinity response characteristics and stability of both FPI sensors reveals that FPI1 demonstrated sensitivities with values of 0.72 nm/°C and 0.076 nm/%, while FPI2 exhibits sensitivities with values of −0.04 nm/°C and −0.29 nm/%. Stability tests reveal maximum wavelength drifts of 0.08 nm and 0.04 nm under the temperature condition of 30 °C and salinity condition of 2 %, corresponding to measurement errors of 0.11 °C and 0.14 % for temperature and salinity, respectively. In repeatability experiments, the relative standard deviations for temperature and salinity sensitivities are 2 % and 0.52 %, respectively, demonstrating excellent stability and reproducibility. This study innovatively proposes a novel high-sensitivity, low-crosstalk solution for simultaneous temperature-salinity measurement based on a dual-cavity structure integrated within a single tube. It effectively overcomes challenges in traditional marine environmental monitoring, such as parameter coupling interference and insufficient sensitivity, providing a superior new technical pathway for precise sensing of ocean temperature-salinity fields.
{"title":"Low-crosstalk compact fiber-optic temperature-salt sensor based on dual-cavity functional partitioning design in a single tube","authors":"Yanxia Chen , Fengyuan Chen , Xinhong Huang , Yantai Liang , Shuangqiang Liu , Le Luo","doi":"10.1016/j.yofte.2025.104548","DOIUrl":"10.1016/j.yofte.2025.104548","url":null,"abstract":"<div><div>The present study puts forward an optical fiber sensor utilizing the Fabry-Perot interferometer (FPI) for simultaneous temperature and salinity measurement, which adopts a dual-cavity structure integrated within a single tube. Functional partitioning design resolves temperature-salinity crosstalk issues. The sensor employs a quartz capillary tube (SCT) to construct a cascaded structure comprising a UV-cured resin cavity (FPI<sub>1</sub>) and a polyimide-coated gas cavity (FPI<sub>2</sub>). It leverages the thermal expansion effect of the UV-cured resin and the salt-induced swelling effect of polyimide to realize measuring temperature and salinity simultaneously. Through finite element analysis, the polyimide film thickness and cavity length are optimized to minimize temperature-salinity crosstalk while balancing salinity sensitivity and response time, yielding optimal response characteristics: FPI<sub>1</sub> exhibits sensitivity of 0.77 nm/°C for temperature and 0.078 nm/% for salinity, while FPI<sub>2</sub> exhibited sensitivities of −0.038 nm/°C and −0.25 nm/%. To validate the theoretical analysis, experimental testing of the temperature-salinity response characteristics and stability of both FPI sensors reveals that FPI<sub>1</sub> demonstrated sensitivities with values of 0.72 nm/°C and 0.076 nm/%, while FPI<sub>2</sub> exhibits sensitivities with values of −0.04 nm/°C and −0.29 nm/%. Stability tests reveal maximum wavelength drifts of 0.08 nm and 0.04 nm under the temperature condition of 30 °C and salinity condition of 2 %, corresponding to measurement errors of 0.11 °C and 0.14 % for temperature and salinity, respectively. In repeatability experiments, the relative standard deviations for temperature and salinity sensitivities are 2 % and 0.52 %, respectively, demonstrating excellent stability and reproducibility. This study innovatively proposes a novel high-sensitivity, low-crosstalk solution for simultaneous temperature-salinity measurement based on a dual-cavity structure integrated within a single tube. It effectively overcomes challenges in traditional marine environmental monitoring, such as parameter coupling interference and insufficient sensitivity, providing a superior new technical pathway for precise sensing of ocean temperature-salinity fields.</div></div>","PeriodicalId":19663,"journal":{"name":"Optical Fiber Technology","volume":"98 ","pages":"Article 104548"},"PeriodicalIF":2.7,"publicationDate":"2026-05-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145885423","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 : 2026-05-01Epub Date: 2025-12-26DOI: 10.1016/j.yofte.2025.104544
Olga N. Egorova , Yaroslav V. Kravchenko , Sergey G. Zhuravlev , Vladimir V. Velmiskin , Valery M. Mashinsky , Andrey E. Levchenko , Sergey L. Semjonov
In this paper, we propose and demonstrate a high-sensitivity temperature sensor based on in-line Mach-Zehnder interferometers exploiting the Vernier effect. Individual in-line Mach-Zehnder interferometers were fabricated by splicing a segment of inner-cladding fiber between two conventional single-mode fibers. The inner-cladding fiber is designed to support only a few cladding modes, which are insensitive to the ambient refractive index. This results in a regular and stable interference spectrum for each Mach-Zehnder interferometer. The fiber core was doped with 75 mol% germanium dioxide. High core doping produces a large effective refractive index difference between the core mode and the inner-cladding modes, providing a high density of interference points (dips or peaks of the superimposed spectrum) per unit wavelength interval, which is beneficial for envelope calculation. The temperature sensitivity of a single Mach-Zehnder interferometer was measured to be 53 pm/°C. By connecting two Mach-Zehnder interferometer with slightly different free spectral ranges in parallel, a 22-fold sensitivity enhancement via the Vernier effect was achieved, resulting in a temperature sensitivity of 1.16 nm/°C over the range of 23–200 °C.
{"title":"Mach-Zehnder interferometer temperature sensor based on inner cladding fiber and the Vernier effect","authors":"Olga N. Egorova , Yaroslav V. Kravchenko , Sergey G. Zhuravlev , Vladimir V. Velmiskin , Valery M. Mashinsky , Andrey E. Levchenko , Sergey L. Semjonov","doi":"10.1016/j.yofte.2025.104544","DOIUrl":"10.1016/j.yofte.2025.104544","url":null,"abstract":"<div><div>In this paper, we propose and demonstrate a high-sensitivity temperature sensor based on in-line Mach-Zehnder interferometers exploiting the Vernier effect. Individual in-line Mach-Zehnder interferometers were fabricated by splicing a segment of inner-cladding fiber between two conventional single-mode fibers. The inner-cladding fiber is designed to support only a few cladding modes, which are insensitive to the ambient refractive index. This results in a regular and stable interference spectrum for each Mach-Zehnder interferometer. The fiber core was doped with 75 mol% germanium dioxide. High core doping produces a large effective refractive index difference between the core mode and the inner-cladding modes, providing a high density of interference points (dips or peaks of the superimposed spectrum) per unit wavelength interval, which is beneficial for envelope calculation. The temperature sensitivity of a single Mach-Zehnder interferometer was measured to be 53 pm/°C. By connecting two Mach-Zehnder interferometer with slightly different free spectral ranges in parallel, a 22-fold sensitivity enhancement via the Vernier effect was achieved, resulting in a temperature sensitivity of 1.16 nm/°C over the range of 23–200 °C.</div></div>","PeriodicalId":19663,"journal":{"name":"Optical Fiber Technology","volume":"98 ","pages":"Article 104544"},"PeriodicalIF":2.7,"publicationDate":"2026-05-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145841863","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 : 2026-05-01Epub Date: 2025-12-23DOI: 10.1016/j.yofte.2025.104543
Ling Chen , Minghong Wang , Liqiang Zhang , Zhen Tian , Fan Zhang , Qiang Wu
A high-precision dual-parameter simultaneous measurement sensor was proposed and developed by cascading a fiber Bragg grating (FBG) and a hollow-core Bragg fiber (HCBF) with a length of 5 mm. Due to the anti-resonant mode in the HCBF and its unique hollow structure, the transmission spectrum exhibits periodic resonance dips with high visibility and low transmission loss. Experimental results demonstrate that the resonance wavelength dips of the transmission spectrum are independent to the length of the HCBF. The HCBF sensor and FBG have different temperature (21.02 pm/℃ and 10.95 pm/℃, respectively) and strain sensitivities (−0.58 pm/με and 0.98 pm/με, respectively), which enables simultaneous measurement of both temperature and strain by employing a 2 × 2 sensitivity coefficient matrix.
{"title":"Dual-parameter simultaneous measurement sensor based on antiresonance mechanism","authors":"Ling Chen , Minghong Wang , Liqiang Zhang , Zhen Tian , Fan Zhang , Qiang Wu","doi":"10.1016/j.yofte.2025.104543","DOIUrl":"10.1016/j.yofte.2025.104543","url":null,"abstract":"<div><div>A high-precision dual-parameter simultaneous measurement sensor was proposed and developed by cascading a fiber Bragg grating (FBG) and a hollow-core Bragg fiber (HCBF) with a length of 5 mm. Due to the anti-resonant mode in the HCBF and its unique hollow structure, the transmission spectrum exhibits periodic resonance dips with high visibility and low transmission loss. Experimental results demonstrate that the resonance wavelength dips of the transmission spectrum are independent to the length of the HCBF. The HCBF sensor and FBG have different temperature (21.02 pm/℃ and 10.95 pm/℃, respectively) and strain sensitivities (−0.58 pm/με and 0.98 pm/με, respectively), which enables simultaneous measurement of both temperature and strain by employing a 2 × 2 sensitivity coefficient matrix.</div></div>","PeriodicalId":19663,"journal":{"name":"Optical Fiber Technology","volume":"98 ","pages":"Article 104543"},"PeriodicalIF":2.7,"publicationDate":"2026-05-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145841861","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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