This study presents a tellurite fiber optic sensor capable of robust temperature monitoring in complex multi-physical field environments. The sensing unit comprises a coreless Er3+/Yb3+ co-doped tellurite fiber integrated with two multi-mode fibers for pump light delivery and up-conversion fluorescence collection. A tapered high-borosilicate glass tube sealed with UV-curable adhesive is adopted to ensure robustness and hermeticity. The temperature-dependent characteristics of the UC fluorescence spectra are investigated under 980 nm laser excitation, and temperature demodulation is performed based on the fluorescence intensity ratio (FIR) technique, revealing a high regression coefficient (R2 = 99.85%) between FIR and temperature. The proposed sensor maintains exceptional (FIR error on the order of 10−3) despite long periods of operation, mechanical vibration, and pressure exposure. In high-humidity environments, the maximum transient temperature deviation from reference values is 1 K. The proposed temperature sensor is capable of providing robust anti-interference temperature monitoring in complex multi-physical field environments.
{"title":"Tellurite Fiber Optic Sensor With Borosilicate Encapsulation for Robust Temperature Monitoring in Complex Multi-Physical Field Environments","authors":"Zhiyuan Yin;Wei Liu;Qianjin Wang;Xue Zhou;Xin Yan;Yong Zhao;Tonglei Cheng","doi":"10.1109/JLT.2025.3627257","DOIUrl":"https://doi.org/10.1109/JLT.2025.3627257","url":null,"abstract":"This study presents a tellurite fiber optic sensor capable of robust temperature monitoring in complex multi-physical field environments. The sensing unit comprises a coreless Er<sup>3+</sup>/Yb<sup>3+</sup> co-doped tellurite fiber integrated with two multi-mode fibers for pump light delivery and up-conversion fluorescence collection. A tapered high-borosilicate glass tube sealed with UV-curable adhesive is adopted to ensure robustness and hermeticity. The temperature-dependent characteristics of the UC fluorescence spectra are investigated under 980 nm laser excitation, and temperature demodulation is performed based on the fluorescence intensity ratio (FIR) technique, revealing a high regression coefficient (R<sup>2</sup> = 99.85%) between FIR and temperature. The proposed sensor maintains exceptional (FIR error on the order of 10<sup>−3</sup>) despite long periods of operation, mechanical vibration, and pressure exposure. In high-humidity environments, the maximum transient temperature deviation from reference values is 1 K. The proposed temperature sensor is capable of providing robust anti-interference temperature monitoring in complex multi-physical field environments.","PeriodicalId":16144,"journal":{"name":"Journal of Lightwave Technology","volume":"44 1","pages":"372-378"},"PeriodicalIF":4.8,"publicationDate":"2025-10-30","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145814461","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2025-10-30DOI: 10.1109/JLT.2025.3626746
Jiazhen Ji;Jiageng Chen;Zhengyuan Xiao;Zhengwen Li;Zuyuan He
Distributed acoustic sensing (DAS) has become a powerful technique for large-scale and high-density monitoring of acoustic wave or vibration. A key limitation to the strain measurement range of DAS systems is that phase variation between adjacent sampling points must remain within $(-pi, pi ]$; otherwise, phase wrapping occurs. Since a higher sampling rate shortens sampling interval, it reduces the phase variation between sampling points induced by a given strain, thus allowing the accumulated phase to exceed $(-pi, pi ]$ and enabling a larger strain measurement. In practice, frequency division multiplexing (FDM) is an effective technique to multiply the sampling rate by using N frequency components. Conventional FDM DAS requires that no phase wrapping occurs in the demodulated phases of each frequency component. As a result, the conventional FDM does not extend the strain measurement range although it enhances the sampling rate. In this work, we propose a scheme to simultaneously improve the frequency response range and the strain measurement range of DAS systems. The scheme adopts a pulse sequence consisting of two FDM pulse trains combined with a multi-frequency phase unwrapping algorithm. In a demonstration experiment over a 50 km sensing fiber, the frequency response range is extended from 1 kHz to 4 kHz, and the strain measurement range is also increased to nearly four times. A 1.2 kHz sinusoidal strain signal with an amplitude of 80.0 n$epsilon$p-p is successfully reconstructed, demonstrating the capability to recover signals that cannot be measured by any single frequency component because of insufficient sampling rate or phase wrapping.
分布式声传感技术（DAS）已成为大规模、高密度监测声波或振动的有力技术。DAS系统应变测量范围的一个关键限制是相邻采样点之间的相位变化必须保持在$(-pi, pi ]$以内；否则，将发生阶段包装。由于较高的采样率缩短了采样间隔，因此减小了由给定应变引起的采样点之间的相位变化，从而使累积相位超过$(-pi, pi ]$，从而实现更大的应变测量。在实际应用中，频分复用（FDM）是一种利用N个频率分量来提高采样率的有效方法。传统的FDM DAS要求在每个频率分量的解调相位中不发生相位包裹。因此，传统的FDM虽然提高了采样率，但没有扩大应变测量范围。在这项工作中，我们提出了一种同时提高DAS系统频率响应范围和应变测量范围的方案。该方案采用由两个FDM脉冲序列组成的脉冲序列，并结合多频相位展开算法。在50公里传感光纤的演示实验中，频率响应范围从1 kHz扩展到4 kHz，应变测量范围也增加到近4倍。一个1.2 kHz的振幅为80.0 n $epsilon$ p-p的正弦应变信号被成功重建，证明了恢复信号的能力，无法测量任何单一的频率成分，因为采样率或相位包裹不足。
{"title":"Strain Measurement Range Extension in Distributed Acoustic Sensor Based on Multi-Frequency Phase Unwrapping","authors":"Jiazhen Ji;Jiageng Chen;Zhengyuan Xiao;Zhengwen Li;Zuyuan He","doi":"10.1109/JLT.2025.3626746","DOIUrl":"https://doi.org/10.1109/JLT.2025.3626746","url":null,"abstract":"Distributed acoustic sensing (DAS) has become a powerful technique for large-scale and high-density monitoring of acoustic wave or vibration. A key limitation to the strain measurement range of DAS systems is that phase variation between adjacent sampling points must remain within <inline-formula><tex-math>$(-pi, pi ]$</tex-math></inline-formula>; otherwise, phase wrapping occurs. Since a higher sampling rate shortens sampling interval, it reduces the phase variation between sampling points induced by a given strain, thus allowing the accumulated phase to exceed <inline-formula><tex-math>$(-pi, pi ]$</tex-math></inline-formula> and enabling a larger strain measurement. In practice, frequency division multiplexing (FDM) is an effective technique to multiply the sampling rate by using <italic>N</i> frequency components. Conventional FDM DAS requires that no phase wrapping occurs in the demodulated phases of each frequency component. As a result, the conventional FDM does not extend the strain measurement range although it enhances the sampling rate. In this work, we propose a scheme to simultaneously improve the frequency response range and the strain measurement range of DAS systems. The scheme adopts a pulse sequence consisting of two FDM pulse trains combined with a multi-frequency phase unwrapping algorithm. In a demonstration experiment over a 50 km sensing fiber, the frequency response range is extended from 1 kHz to 4 kHz, and the strain measurement range is also increased to nearly four times. A 1.2 kHz sinusoidal strain signal with an amplitude of 80.0 n<inline-formula><tex-math>$epsilon$</tex-math></inline-formula><sub>p-p</sub> is successfully reconstructed, demonstrating the capability to recover signals that cannot be measured by any single frequency component because of insufficient sampling rate or phase wrapping.","PeriodicalId":16144,"journal":{"name":"Journal of Lightwave Technology","volume":"44 1","pages":"362-371"},"PeriodicalIF":4.8,"publicationDate":"2025-10-30","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145814470","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2025-10-28DOI: 10.1109/JLT.2025.3626391
Masanori Koshiba;Kunimasa Saitoh
The so-called effective bending radius (EBR) for a stress-effect correction is required in order to fit calculated bend losses in single-core fibers with measured results; however, the EBR has been hardly used for evaluating the stress effects on the inter-core crosstalk (XT) and inter-core skew (ICS) in bent multicore fibers (MCFs). In this paper, first, revisiting and comprehensively reviewing the EBR derivation method, we confirm that there exist two different EBR values, ${{R}_{mathrm{eff}}} approx $1.28$R$ and ${{R}_{mathrm{eff}}} approx $1.4$R$ with $R$ being the bending radius, depending on the underlying assumptions. Next, incorporating the EBR into the XT and ICS formulae, we evaluate the stress effects on the XT and ICS in bent MCFs, and reveal that the EBR ${{R}_{mathrm{eff}}}$= 1.4$R$ leads to more consistent results between calculations and measurements.
{"title":"Stress Effects on Crosstalk and Skew in Bent Multicore Fibers: A Revisit to Effective Bending Radius","authors":"Masanori Koshiba;Kunimasa Saitoh","doi":"10.1109/JLT.2025.3626391","DOIUrl":"https://doi.org/10.1109/JLT.2025.3626391","url":null,"abstract":"The so-called effective bending radius (EBR) for a stress-effect correction is required in order to fit calculated bend losses in single-core fibers with measured results; however, the EBR has been hardly used for evaluating the stress effects on the inter-core crosstalk (XT) and inter-core skew (ICS) in bent multicore fibers (MCFs). In this paper, first, revisiting and comprehensively reviewing the EBR derivation method, we confirm that there exist two different EBR values, <inline-formula><tex-math>${{R}_{mathrm{eff}}} approx $</tex-math></inline-formula>1.28<inline-formula><tex-math>$R$</tex-math></inline-formula> and <inline-formula><tex-math>${{R}_{mathrm{eff}}} approx $</tex-math></inline-formula>1.4<inline-formula><tex-math>$R$</tex-math></inline-formula> with <inline-formula><tex-math>$R$</tex-math></inline-formula> being the bending radius, depending on the underlying assumptions. Next, incorporating the EBR into the XT and ICS formulae, we evaluate the stress effects on the XT and ICS in bent MCFs, and reveal that the EBR <inline-formula><tex-math>${{R}_{mathrm{eff}}}$</tex-math></inline-formula>= 1.4<inline-formula><tex-math>$R$</tex-math></inline-formula> leads to more consistent results between calculations and measurements.","PeriodicalId":16144,"journal":{"name":"Journal of Lightwave Technology","volume":"44 1","pages":"296-302"},"PeriodicalIF":4.8,"publicationDate":"2025-10-28","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://ieeexplore.ieee.org/stamp/stamp.jsp?tp=&arnumber=11220214","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145814513","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
This paper presents a novel, compact, all-fiber multi-parameter sensor based on orthogonal off-axis fiber Bragg gratings (FBGs) inscribed in a few-mode fiber (FMF) using femtosecond laser point-by-point (PbP) direct writing technique. The effects of different FMF transmission lengths and grating off-axis displacements on the excitation intensities of various modes are investigated. The fusion point between the single-mode fiber (SMF) and FMF functions as a torsion sensing element, while the FM-FBGs are employed for two-dimensional vector bending detection. By analyzing intensity variations of both self-coupled and cross-coupled mode reflection peaks, the sensor enables simultaneous measurement of torsion and bending through distinct modal responses. In addition, axial strain is monitored via idle wavelength channels, thereby achieving the simultaneous measurement of torsion, two-dimensional vector bending, and axial strain in a compact all-fiber configuration.
{"title":"Multi-Parameter Sensor Based on Orthogonal Off-Axis Few-Mode FBGs via Femtosecond Laser Point-by-Point Technique","authors":"Weitao Luo;Tianxin Duan;Chen Yang;Ruohui Wang;Dan Su;Xueguang Qiao","doi":"10.1109/JLT.2025.3625768","DOIUrl":"https://doi.org/10.1109/JLT.2025.3625768","url":null,"abstract":"This paper presents a novel, compact, all-fiber multi-parameter sensor based on orthogonal off-axis fiber Bragg gratings (FBGs) inscribed in a few-mode fiber (FMF) using femtosecond laser point-by-point (PbP) direct writing technique. The effects of different FMF transmission lengths and grating off-axis displacements on the excitation intensities of various modes are investigated. The fusion point between the single-mode fiber (SMF) and FMF functions as a torsion sensing element, while the FM-FBGs are employed for two-dimensional vector bending detection. By analyzing intensity variations of both self-coupled and cross-coupled mode reflection peaks, the sensor enables simultaneous measurement of torsion and bending through distinct modal responses. In addition, axial strain is monitored via idle wavelength channels, thereby achieving the simultaneous measurement of torsion, two-dimensional vector bending, and axial strain in a compact all-fiber configuration.","PeriodicalId":16144,"journal":{"name":"Journal of Lightwave Technology","volume":"44 1","pages":"338-345"},"PeriodicalIF":4.8,"publicationDate":"2025-10-27","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145814462","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
A voltage sensing scheme with high resolution utilizing the Pockels effect of lithium niobate (LiNbO3) crystal based on cascaded microwave photonic filters (MPFs) is proposed and experimentally validated. The key component of the system is a phase-controlled MPF composed of a Mach-Zehnder modulator (MZM), a LiNbO3 crystal and a linearly chirped fiber Bragg grating (LCFBG). Thanks to the Pockels effect, when the voltage is applied, phase difference between the orthogonally polarized lights in LiNbO3 crystal is generated, which is converted to a phase shift between the orthogonal optical carrier and first order sidebands using the MZM. By utilizing the dispersion of the LCFBG, the center frequency of the phase-controlled MPF is determined by the phase difference between the orthogonal optical carrier and first order sidebands. Consequently, the voltage can be detected by monitoring the frequency response shift of the phase-controlled MPF. The experimental results demonstrate a sensitivity of 1.45 MHz/V with a theoretical resolution of 7×10−7 V. Additionally, a dual-tap MPF incorporating two optical fibers of slightly different lengths is cascaded with the phase-controlled MPF. Since the phase-controlled MPF and dual-tap MPF show different voltage and temperature sensitivities, by monitoring the variations of two frequency responses, the simultaneous measurement for voltage and temperature can be realized. Moreover, the voltage can be demodulated by simply detecting output power variations at certain frequency, yielding a sensitivity of 1.15×10−5 mW/V, which can further improve the demodulation efficiency and speed. The proposed system providing flexible and efficient demodulation solutions with high resolution and high speed characteristics, may be widely applied in voltage monitoring in smart grids.
{"title":"High-Resolution Voltage Sensing with Temperature-Compensation Based on Cascaded Microwave Photonic Filters Utilizing the Pockels Effect of LiNbO3 Crystal","authors":"Beilei Wu;Yihua Cai;Bin Yin;Shiying Xiao;Zishuo Zhang;Muguang Wang;Fengping Yan;Li Pei","doi":"10.1109/JLT.2025.3626019","DOIUrl":"https://doi.org/10.1109/JLT.2025.3626019","url":null,"abstract":"A voltage sensing scheme with high resolution utilizing the Pockels effect of lithium niobate (LiNbO<sub>3</sub>) crystal based on cascaded microwave photonic filters (MPFs) is proposed and experimentally validated. The key component of the system is a phase-controlled MPF composed of a Mach-Zehnder modulator (MZM), a LiNbO<sub>3</sub> crystal and a linearly chirped fiber Bragg grating (LCFBG). Thanks to the Pockels effect, when the voltage is applied, phase difference between the orthogonally polarized lights in LiNbO<sub>3</sub> crystal is generated, which is converted to a phase shift between the orthogonal optical carrier and first order sidebands using the MZM. By utilizing the dispersion of the LCFBG, the center frequency of the phase-controlled MPF is determined by the phase difference between the orthogonal optical carrier and first order sidebands. Consequently, the voltage can be detected by monitoring the frequency response shift of the phase-controlled MPF. The experimental results demonstrate a sensitivity of 1.45 MHz/V with a theoretical resolution of 7×10<sup>−7</sup> V. Additionally, a dual-tap MPF incorporating two optical fibers of slightly different lengths is cascaded with the phase-controlled MPF. Since the phase-controlled MPF and dual-tap MPF show different voltage and temperature sensitivities, by monitoring the variations of two frequency responses, the simultaneous measurement for voltage and temperature can be realized. Moreover, the voltage can be demodulated by simply detecting output power variations at certain frequency, yielding a sensitivity of 1.15×10<sup>−5</sup> mW/V, which can further improve the demodulation efficiency and speed. The proposed system providing flexible and efficient demodulation solutions with high resolution and high speed characteristics, may be widely applied in voltage monitoring in smart grids.","PeriodicalId":16144,"journal":{"name":"Journal of Lightwave Technology","volume":"44 1","pages":"393-400"},"PeriodicalIF":4.8,"publicationDate":"2025-10-27","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145814509","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2025-10-23DOI: 10.1109/JLT.2025.3624846
Tian Tian;Xiao Li;Yiwei Ma;Tao Geng
In this paper, a fiber-optic bionic superficial neuromast sensor (BSNFS) for flow measurement is proposed and validated, which utilizes multi-mode fiber (MMF) as the sensing unit. By employing arc discharge, a significant structural deformation is induced within the core region of the MMF. This fabrication process not only establishes a sensing region with strong refractive index modulation (RIM), but also simultaneously forms a bionic cilium-like structure by bending the fiber at an 87° angle with respect to its primary axis. The bio-inspired cilium is capable of receiving mechanical stimuli and transducing the mechanosensory signal to the fusion point of the MMF. This transduction modifies the original light transmission characteristics within the optical path, thereby achieving the conversion process from “cilium-based mechanical perception” to “optical signal transmission”. In experiments, the proposed sensor exhibits excellent sensitivity and tunability in flow velocity measurement. By adjusting the cilium length (1.4–3.5 cm), tunable detection can be achieved within the flow velocity range of 0.046–0.140 m/s. Correspondingly, the sensitivity ranges from 351.4-3614.9 nm/(m/s). Furthermore, benefiting from the asymmetric sensing structure design, the sensor demonstrates vector detection capability.
{"title":"Ultra-Sensitive Bioinspired Photonic Flow Sensor With Mechanical-Photonics Coupling Sensing Capabilities","authors":"Tian Tian;Xiao Li;Yiwei Ma;Tao Geng","doi":"10.1109/JLT.2025.3624846","DOIUrl":"https://doi.org/10.1109/JLT.2025.3624846","url":null,"abstract":"In this paper, a fiber-optic bionic superficial neuromast sensor (BSNFS) for flow measurement is proposed and validated, which utilizes multi-mode fiber (MMF) as the sensing unit. By employing arc discharge, a significant structural deformation is induced within the core region of the MMF. This fabrication process not only establishes a sensing region with strong refractive index modulation (RIM), but also simultaneously forms a bionic cilium-like structure by bending the fiber at an 87° angle with respect to its primary axis. The bio-inspired cilium is capable of receiving mechanical stimuli and transducing the mechanosensory signal to the fusion point of the MMF. This transduction modifies the original light transmission characteristics within the optical path, thereby achieving the conversion process from “cilium-based mechanical perception” to “optical signal transmission”. In experiments, the proposed sensor exhibits excellent sensitivity and tunability in flow velocity measurement. By adjusting the cilium length (1.4–3.5 cm), tunable detection can be achieved within the flow velocity range of 0.046–0.140 m/s. Correspondingly, the sensitivity ranges from 351.4-3614.9 nm/(m/s). Furthermore, benefiting from the asymmetric sensing structure design, the sensor demonstrates vector detection capability.","PeriodicalId":16144,"journal":{"name":"Journal of Lightwave Technology","volume":"44 1","pages":"323-330"},"PeriodicalIF":4.8,"publicationDate":"2025-10-23","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145814473","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2025-10-22DOI: 10.1109/JLT.2025.3624333
Xiaojun Chen;Da Zhang;Ya Zhang;Fenghuan Hao;Ang Li;Shengchun Liu
This paper presents a MEMS-based underwater acoustic sensor featuring a dual hetero-structure silicon diaphragm, operating on the principle of extrinsic Fabry-Perot interferometer(EFPI). The sensor exhibits miniaturized dimensions, high sensitivity, and excellent consistency. The hetero-structure consists of SiO2 and Si3N4 layers fabricated through thermal oxidation and chemical vapor deposition(CVD) on silicon wafers. Photolithography and reactive ion etching(RIE) techniques were employed to create a composite microstructure combining a central planar region with concentric annular corrugations. This dual hetero-structure design effectively mitigates internal stresses while maintaining structural integrity and enabling linear high-sensitivity response. A step structure was integrated to precisely control the Fabry-Perot(F-P) cavity length and mirror alignment, ensuring stable optical performance. The sensor incorporates bend-insensitive small-mode-field fiber to construct the EFPI, significantly enhancing anti-interference capability during signal transmission. Three prototype sensors with diaphragm diameters of ϕ1.3 mm, ϕ1.1 mm, and ϕ0.9 mm (uniform thickness: 1.3 μm) were fabricated. The quartz fiber ferrules were precisely aligned and bonded using epoxy resin to form complete acoustic sensors. Broadband interference spectra characterization revealed an average F-P cavity length of 46 μm with less than 1 μm variation and optical visibility exceeding 0.94, demonstrating excellent optical stability. Acoustic sensitivity tests showed a maximum sensitivity of −150 dB (ref rad/ μPa) with frequency response fluctuations within ±2 dB across the 20 Hz–2 kHz band. The inter-device sensitivity variation was also maintained below ±2 dB, with phase inconsistency limited to ±5° throughout the operational bandwidth. Additional measurements indicated a noise floor below −90 dB (ref rad) and a linear dynamic range exceeding 60dB. The proposed MEMS sensor architecture and fabrication methodology demonstrate significant potential for cost-effective, high-performance mass production of underwater acoustic sensors.
{"title":"Optical Fiber Fabry–Perot Underwater Acoustic Sensor Based on Dual Hetero-Structured Silicon Micro-Diaphragm","authors":"Xiaojun Chen;Da Zhang;Ya Zhang;Fenghuan Hao;Ang Li;Shengchun Liu","doi":"10.1109/JLT.2025.3624333","DOIUrl":"https://doi.org/10.1109/JLT.2025.3624333","url":null,"abstract":"This paper presents a MEMS-based underwater acoustic sensor featuring a dual hetero-structure silicon diaphragm, operating on the principle of extrinsic Fabry-Perot interferometer(EFPI). The sensor exhibits miniaturized dimensions, high sensitivity, and excellent consistency. The hetero-structure consists of SiO<sub>2</sub> and Si<sub>3</sub>N<sub>4</sub> layers fabricated through thermal oxidation and chemical vapor deposition(CVD) on silicon wafers. Photolithography and reactive ion etching(RIE) techniques were employed to create a composite microstructure combining a central planar region with concentric annular corrugations. This dual hetero-structure design effectively mitigates internal stresses while maintaining structural integrity and enabling linear high-sensitivity response. A step structure was integrated to precisely control the Fabry-Perot(F-P) cavity length and mirror alignment, ensuring stable optical performance. The sensor incorporates bend-insensitive small-mode-field fiber to construct the EFPI, significantly enhancing anti-interference capability during signal transmission. Three prototype sensors with diaphragm diameters of ϕ1.3 mm, ϕ1.1 mm, and ϕ0.9 mm (uniform thickness: 1.3 μm) were fabricated. The quartz fiber ferrules were precisely aligned and bonded using epoxy resin to form complete acoustic sensors. Broadband interference spectra characterization revealed an average F-P cavity length of 46 μm with less than 1 μm variation and optical visibility exceeding 0.94, demonstrating excellent optical stability. Acoustic sensitivity tests showed a maximum sensitivity of −150 dB (ref rad/ μPa) with frequency response fluctuations within ±2 dB across the 20 Hz–2 kHz band. The inter-device sensitivity variation was also maintained below ±2 dB, with phase inconsistency limited to ±5° throughout the operational bandwidth. Additional measurements indicated a noise floor below −90 dB (ref rad) and a linear dynamic range exceeding 60dB. The proposed MEMS sensor architecture and fabrication methodology demonstrate significant potential for cost-effective, high-performance mass production of underwater acoustic sensors.","PeriodicalId":16144,"journal":{"name":"Journal of Lightwave Technology","volume":"44 1","pages":"353-361"},"PeriodicalIF":4.8,"publicationDate":"2025-10-22","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145814469","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2025-10-22DOI: 10.1109/JLT.2025.3624232
Jinfeng Liu;Jie Huang;Yingxian Zhang;Xiaoyang Ye;Sijia Tang;Ping Qiu;Ke Wang
The NIR-IV window has emerged as the longest optical window suitable for deep-tissue multiphoton microscopy (MPM). Linearly-polarized soliton laser source has been exclusively used for excitation so far. In order to boost pulse energy in this window, here we demonstrate a novel soliton source, based on vector soliton self-frequency shift (SSFS) in a birefringent polarization maintaining large-mode-area (PM LMA) fiber. This vector soliton source has temporally overlapping, yet spectrally slightly shifts components polarized along the principal axes of the fiber. The vector soliton energy is twice higher than those of linearly-polarized solitons. Three-photon images excited by the vector soliton show MPM signals enhanced by ∼9 times ex vivo, and ∼7 times in mouse in vivo, compared with linearly-polarized soliton excitation. Vector SSFS is thus a promising technology for MPM for the NIR-IV window.
{"title":"Vector Soliton Source for Multiphoton Microscopy in the NIR-IV Window","authors":"Jinfeng Liu;Jie Huang;Yingxian Zhang;Xiaoyang Ye;Sijia Tang;Ping Qiu;Ke Wang","doi":"10.1109/JLT.2025.3624232","DOIUrl":"https://doi.org/10.1109/JLT.2025.3624232","url":null,"abstract":"The NIR-IV window has emerged as the longest optical window suitable for deep-tissue multiphoton microscopy (MPM). Linearly-polarized soliton laser source has been exclusively used for excitation so far. In order to boost pulse energy in this window, here we demonstrate a novel soliton source, based on vector soliton self-frequency shift (SSFS) in a birefringent polarization maintaining large-mode-area (PM LMA) fiber. This vector soliton source has temporally overlapping, yet spectrally slightly shifts components polarized along the principal axes of the fiber. The vector soliton energy is twice higher than those of linearly-polarized solitons. Three-photon images excited by the vector soliton show MPM signals enhanced by ∼9 times ex vivo, and ∼7 times in mouse in vivo, compared with linearly-polarized soliton excitation. Vector SSFS is thus a promising technology for MPM for the NIR-IV window.","PeriodicalId":16144,"journal":{"name":"Journal of Lightwave Technology","volume":"44 1","pages":"260-266"},"PeriodicalIF":4.8,"publicationDate":"2025-10-22","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145814468","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Transition metal dichalcogenides (TMDs), particularly molybdenum ditelluride (MoTe2), exhibit unique phase-dependent properties that make this a promising candidate in optoelectronic and optical applications, including photodetectors, light-emitting diodes, optical modulators, and saturable absorbers (SAs). Although previous studies have attempted to utilize MoTe2 SA in pulsed fiber lasers, a comprehensive study investigating the impact of these distinct phases on the performance of fiber lasers remains largely unexplored. This study investigates the nonlinear optical properties and fiber laser performance of multilayered 1T’-MoTe2 (semi-metallic phase) and 2H-MoTe2 (semiconducting phase) SAs utilizing evanescent field interactions. Our findings reveal that 1T’-MoTe2, characterized by a stronger saturable absorption with high modulation depth, enables the generation of Q-switched laser pulses, while 2H-MoTe2, with its comparatively lower saturable absorption coefficient and a moderate modulation depth, facilitates stable mode-locked femtosecond pulse generation. This work provides insights into the phase-dependent saturable absorption characteristics of MoTe2, offering guidance for selecting and engineering TMD-based SAs for tailored pulsed fiber laser applications.
{"title":"Phase-Engineered MoTe2 Saturable Absorbers for Diverse Fiber Pulse Laser Operations","authors":"Pulak Chandra Debnath;Hyeonkyeong Kim;Jong Hyuk Yim;Seongju Ha;Siheon Ryu;Taeyol Min;Youngdong Yoo;Dong-Il Yeom","doi":"10.1109/JLT.2025.3623401","DOIUrl":"https://doi.org/10.1109/JLT.2025.3623401","url":null,"abstract":"Transition metal dichalcogenides (TMDs), particularly molybdenum ditelluride (MoTe<sub>2</sub>), exhibit unique phase-dependent properties that make this a promising candidate in optoelectronic and optical applications, including photodetectors, light-emitting diodes, optical modulators, and saturable absorbers (SAs). Although previous studies have attempted to utilize MoTe<sub>2</sub> SA in pulsed fiber lasers, a comprehensive study investigating the impact of these distinct phases on the performance of fiber lasers remains largely unexplored. This study investigates the nonlinear optical properties and fiber laser performance of multilayered 1T’-MoTe<sub>2</sub> (semi-metallic phase) and 2H-MoTe<sub>2</sub> (semiconducting phase) SAs utilizing evanescent field interactions. Our findings reveal that 1T’-MoTe<sub>2</sub>, characterized by a stronger saturable absorption with high modulation depth, enables the generation of Q-switched laser pulses, while 2H-MoTe<sub>2</sub>, with its comparatively lower saturable absorption coefficient and a moderate modulation depth, facilitates stable mode-locked femtosecond pulse generation. This work provides insights into the phase-dependent saturable absorption characteristics of MoTe<sub>2</sub>, offering guidance for selecting and engineering TMD-based SAs for tailored pulsed fiber laser applications.","PeriodicalId":16144,"journal":{"name":"Journal of Lightwave Technology","volume":"44 1","pages":"273-279"},"PeriodicalIF":4.8,"publicationDate":"2025-10-20","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145814464","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
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