Pub Date : 2025-11-08DOI: 10.1016/j.yofte.2025.104448
Dandan Yang , Fengping Yan , Qi Qin , Ting Li , Chenhao Yu , Xiangdong Wang , Hao Guo , Yuezhi Cai , Wenjie Ji , Youchao Jiang , Qiuyu Huang , Siyu Peng , Ting Feng
In this paper, a self-injection locking technique combining a delay fiber and sub-ring is proposed for the linewidth compression of a single-longitudinal-mode (SLM) laser in the 1.94 µm band. The laser output with an optical signal-to-noise ratio of 74.1 dB and linewidth less than 1 kHz is obtained. Furthermore, to the best of our knowledge, the feedback cavity, which exhibits excellent linewidth compression, was formed by the combination of a sub-ring and delay fiber and has been experimentally demonstrated for the first time. This narrow linewidth SLM fiber laser is highly competitive in advanced coherent light detection fields including coherent Doppler wind lidar, high-speed coherent optical communication, and precise absolute distance coherent measurement.
{"title":"Linewidth reduction of a thulium-holmium co-doped fiber laser to sub-kHz using self-injection locking with an external sub-ring","authors":"Dandan Yang , Fengping Yan , Qi Qin , Ting Li , Chenhao Yu , Xiangdong Wang , Hao Guo , Yuezhi Cai , Wenjie Ji , Youchao Jiang , Qiuyu Huang , Siyu Peng , Ting Feng","doi":"10.1016/j.yofte.2025.104448","DOIUrl":"10.1016/j.yofte.2025.104448","url":null,"abstract":"<div><div>In this paper, a self-injection locking technique combining a delay fiber and sub-ring is proposed for the linewidth compression of a single-longitudinal-mode (SLM) laser in the 1.94 µm band. The laser output with an optical signal-to-noise ratio of 74.1 dB and linewidth less than 1 kHz is obtained. Furthermore, to the best of our knowledge, the feedback cavity, which exhibits excellent linewidth compression, was formed by the combination of a sub-ring and delay fiber and has been experimentally demonstrated for the first time. This narrow linewidth SLM fiber laser is highly competitive in advanced coherent light detection fields including coherent Doppler wind lidar, high-speed coherent optical communication, and precise absolute distance coherent measurement.</div></div>","PeriodicalId":19663,"journal":{"name":"Optical Fiber Technology","volume":"96 ","pages":"Article 104448"},"PeriodicalIF":2.7,"publicationDate":"2025-11-08","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145527241","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 : 2025-11-07DOI: 10.1016/j.yofte.2025.104475
Wa jin, Xiaoqing liu, Xiong gao
In the diagnosis of acute myocardial infarction (AMI), cardiac troponin I serves as the preferred biomarker. Owing to its extremely low diagnostic cutoff concentration in blood, high requirements are imposed on detection sensitivity. In this study, a label-free sensing probe for myocardial injury markers based on high birefringence (Hi-Bi) micro-nano fiber was proposed. Refractive index experiments were conducted using sensing probes with different dimensions. Eventually, a sensing fiber with a diameter of approximately 8.1 μm and a refractive index sensitivity of 1925.4 nm/RIU was selected for the detection of cTn-I at different concentrations. The variation law of spectral wavelength during the binding reaction between cTn-I antigen and antibody, as well as the dynamic response curves of cTn-I antigens at different concentrations, were investigated. A relationship curve between cTn-I antigen concentration and wavelength variation was established, and the limit of detection of the sensor for cTn-I concentration was calculated to be as low as 4.3 pg/mL. This study explores a novel and high-precision approach for cTn-I detection.
{"title":"A label-free micro-nano optical fiber based on the detection of myocardial biomarkers with high birefringence","authors":"Wa jin, Xiaoqing liu, Xiong gao","doi":"10.1016/j.yofte.2025.104475","DOIUrl":"10.1016/j.yofte.2025.104475","url":null,"abstract":"<div><div>In the diagnosis of acute myocardial infarction (AMI), cardiac troponin I serves as the preferred biomarker. Owing to its extremely low diagnostic cutoff concentration in blood, high requirements are imposed on detection sensitivity. In this study, a label-free sensing probe for myocardial injury markers based on high birefringence (Hi-Bi) micro-nano fiber was proposed. Refractive index experiments were conducted using sensing probes with different dimensions. Eventually, a sensing fiber with a diameter of approximately 8.1 μm and a refractive index sensitivity of 1925.4 nm/RIU was selected for the detection of cTn-I at different concentrations. The variation law of spectral wavelength during the binding reaction between cTn-I antigen and antibody, as well as the dynamic response curves of cTn-I antigens at different concentrations, were investigated. A relationship curve between cTn-I antigen concentration and wavelength variation was established, and the limit of detection of the sensor for cTn-I concentration was calculated to be as low as 4.3 pg/mL. This study explores a novel and high-precision approach for cTn-I detection.</div></div>","PeriodicalId":19663,"journal":{"name":"Optical Fiber Technology","volume":"96 ","pages":"Article 104475"},"PeriodicalIF":2.7,"publicationDate":"2025-11-07","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145475609","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 : 2025-11-07DOI: 10.1016/j.yofte.2025.104474
Nurul Izzah S. Wadi , Yu Chen , Ahmed Nady , Ahmad Haziq A. Rosol , Anas A. Latiff , Muhammad Imran M.A. Khudus , Ahmad Shuhaimi A. Bakar
In this work, harmonic mode-locked (HML) pulses were generated in an erbium-doped fiber laser (EDFL) using the multimode interference (MMI) effect within a simple interferometer formed by sandwiching a graded-index multimode fiber (GIMF) between two standard single-mode fibers (SMFs). The core diameter mismatch between the SMF and GIMF induces MMI and enables efficient coupling of high-intensity light, effectively replicating the behavior of a saturable absorber (SA). Fundamental soliton pulses with a repetition rate of 20.89 MHz and a maximum pulse energy of 0.23 nJ were obtained within a pump range of 23.18 to 66.23 mW. As the pump power increased above 66.23 up to 103.12 mW, the laser transitioned to second-order harmonic mode-locking, doubling the repetition rate to 41.70 MHz. This transition arises from gain depletion and pulse peak clamping within the cavity, leading to pulse splitting and harmonic generation. The HML pulses operated at 1573.8 nm with a duration of 290 fs and an exceptionally high signal-to-noise ratio (SNR) of 80 dB, confirming excellent stability. The cost-effective and compact SMF–GIMF–SMF structure thus offers a promising route toward sustainable, high-performance photonic systems for future industrial applications.
{"title":"Harmonic Mode-Locked pulse generation via multimode interference in Graded-Index multimode fiber within an Erbium-Doped fiber laser","authors":"Nurul Izzah S. Wadi , Yu Chen , Ahmed Nady , Ahmad Haziq A. Rosol , Anas A. Latiff , Muhammad Imran M.A. Khudus , Ahmad Shuhaimi A. Bakar","doi":"10.1016/j.yofte.2025.104474","DOIUrl":"10.1016/j.yofte.2025.104474","url":null,"abstract":"<div><div>In this work, harmonic mode-locked (HML) pulses were generated in an erbium-doped fiber laser (EDFL) using the multimode interference (MMI) effect within a simple interferometer formed by sandwiching a graded-index multimode fiber (GIMF) between two standard single-mode fibers (SMFs). The core diameter mismatch between the SMF and GIMF induces MMI and enables efficient coupling of high-intensity light, effectively replicating the behavior of a saturable absorber (SA). Fundamental soliton pulses with a repetition rate of 20.89 MHz and a maximum pulse energy of 0.23 nJ were obtained within a pump range of 23.18 to 66.23 mW. As the pump power increased above 66.23 up to 103.12 mW, the laser transitioned to second-order harmonic mode-locking, doubling the repetition rate to 41.70 MHz. This transition arises from gain depletion and pulse peak clamping within the cavity, leading to pulse splitting and harmonic generation. The HML pulses operated at 1573.8 nm with a duration of 290 fs and an exceptionally high signal-to-noise ratio (SNR) of 80 dB, confirming excellent stability. The cost-effective and compact SMF–GIMF–SMF structure thus offers a promising route toward sustainable, high-performance photonic systems for future industrial applications.</div></div>","PeriodicalId":19663,"journal":{"name":"Optical Fiber Technology","volume":"96 ","pages":"Article 104474"},"PeriodicalIF":2.7,"publicationDate":"2025-11-07","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145475608","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 : 2025-11-07DOI: 10.1016/j.yofte.2025.104460
Xiaoxin Ge , Bo Liu , Jianxin Ren , Yaya Mao , Shuaidong Chen , Xiumin Song , Tingting Sun , Dongxu Zhu , Mengtong Yin , Zining Pan , Wen Han
This paper proposes a symbol-level chaotic masking scheme based on three-dimensional (3D) constellation flip coding. A 3D composite constellation is constructed using regular octagonal diamond shape and regular tetrahedrons as primitive elements. Probabilistic shaping (PS) is introduced to optimize the distribution of constellation points, further enhancing the overall constellation performance. Furthermore, a multi-layer encryption system combining symbol-subcarrier joint perturbation via a 4D multi-phase hyperchaotic system and constellation flip coding encryption is implemented to ensure transmission security. Experimental validation over a 2-km seven-core fiber successfully achieved 59.06 Gb/s orthogonal frequency division multiplexing (OFDM) signal transmission, demonstrating the superior performance of the proposed constellation. At forward error correction (FEC) threshold of 3.8 × 10−3, the receiver sensitivity of the proposed 3D composite constellation exhibited gains of 0.3 dB and 1.21 dB compared to the 32-ary 3D constellation constructed with a regular hexahedron and the traditional 32QAM 2D constellation respectively. Additionally, we achieved a 1.02 dB receiver sensitivity gain at an entropy of 4.4 bits/symbol compared to uniformly distributed constellations. The experimental results also show that the encryption at any layer is breached, the system’s bit error rate (BER) can still reach above 0.5. The encrypted signals showed negligible differences from unencrypted ones, with a key space of 10107 confirming the scheme’s high security and excellent transmission performance. These results highlight its promising potential for future short-reach communication systems.
{"title":"A symbol-level chaotic masking scheme based on three-dimensional constellation flip coding","authors":"Xiaoxin Ge , Bo Liu , Jianxin Ren , Yaya Mao , Shuaidong Chen , Xiumin Song , Tingting Sun , Dongxu Zhu , Mengtong Yin , Zining Pan , Wen Han","doi":"10.1016/j.yofte.2025.104460","DOIUrl":"10.1016/j.yofte.2025.104460","url":null,"abstract":"<div><div>This paper proposes a symbol-level chaotic masking scheme based on three-dimensional (3D) constellation flip coding. A 3D composite constellation is constructed using regular octagonal diamond shape and regular tetrahedrons as primitive elements. Probabilistic shaping (PS) is introduced to optimize the distribution of constellation points, further enhancing the overall constellation performance. Furthermore, a multi-layer encryption system combining symbol-subcarrier joint perturbation via a 4D multi-phase hyperchaotic system and constellation flip coding encryption is implemented to ensure transmission security. Experimental validation over a 2-km seven-core fiber successfully achieved 59.06 Gb/s orthogonal frequency division multiplexing (OFDM) signal transmission, demonstrating the superior performance of the proposed constellation. At forward error correction (FEC) threshold of 3.8 × 10<sup>−3</sup>, the receiver sensitivity of the proposed 3D composite constellation exhibited gains of 0.3 dB and 1.21 dB compared to the 32-ary 3D constellation constructed with a regular hexahedron and the traditional 32QAM 2D constellation respectively. Additionally, we achieved a 1.02 dB receiver sensitivity gain at an entropy of 4.4 bits/symbol compared to uniformly distributed constellations. The experimental results also show that the encryption at any layer is breached, the system’s bit error rate (BER) can still reach above 0.5. The encrypted signals showed negligible differences from unencrypted ones, with a key space of 10<sup>107</sup> confirming the scheme’s high security and excellent transmission performance. These results highlight its promising potential for future short-reach communication systems.</div></div>","PeriodicalId":19663,"journal":{"name":"Optical Fiber Technology","volume":"96 ","pages":"Article 104460"},"PeriodicalIF":2.7,"publicationDate":"2025-11-07","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145475607","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 : 2025-11-05DOI: 10.1016/j.yofte.2025.104473
E. Pedruzzi , C.E.S. Castellani , W. Blanc , A. Leal-Junior
This paper presents an experimental investigation of the spectral and power stability of a random fiber laser (RFL) based on nanoparticle (NP)-doped fiber, under three different passive optical feedback configurations: retroreflector, Faraday rotator, and fiber Bragg grating (FBG). The NP-doped fiber offers enhanced Rayleigh scattering and intrinsic gain, allowing distributed feedback and laser generation. Spectral analysis revealed that the FBG configuration presented the highest spectral stability, with a 91.25% reduction in wavelength variation compared to the retroreflector. The Faraday rotator also contributed to the spectral stability, with a 37.5% reduction. Regarding power stability, the Faraday rotator presented the best performance, with only 1.62% variation, while the FBG provided the highest output power (8.13 dBm), with a 6.1% variation. The retroreflector configuration demonstrated the worst performance in both spectral and power stability. These results confirm that the combination of NP-doped fibers and well-selected passive feedback elements allows the development of more stable and coherent RFLs, expanding their potential for application in sensing, telecommunications, and optical fiber devices.
{"title":"Stability enhancement in random fiber lasers using passive feedback and NP-doped fibers","authors":"E. Pedruzzi , C.E.S. Castellani , W. Blanc , A. Leal-Junior","doi":"10.1016/j.yofte.2025.104473","DOIUrl":"10.1016/j.yofte.2025.104473","url":null,"abstract":"<div><div>This paper presents an experimental investigation of the spectral and power stability of a random fiber laser (RFL) based on nanoparticle (NP)-doped fiber, under three different passive optical feedback configurations: retroreflector, Faraday rotator, and fiber Bragg grating (FBG). The NP-doped fiber offers enhanced Rayleigh scattering and intrinsic gain, allowing distributed feedback and laser generation. Spectral analysis revealed that the FBG configuration presented the highest spectral stability, with a 91.25% reduction in wavelength variation compared to the retroreflector. The Faraday rotator also contributed to the spectral stability, with a 37.5% reduction. Regarding power stability, the Faraday rotator presented the best performance, with only 1.62% variation, while the FBG provided the highest output power (8.13 dBm), with a 6.1% variation. The retroreflector configuration demonstrated the worst performance in both spectral and power stability. These results confirm that the combination of NP-doped fibers and well-selected passive feedback elements allows the development of more stable and coherent RFLs, expanding their potential for application in sensing, telecommunications, and optical fiber devices.</div></div>","PeriodicalId":19663,"journal":{"name":"Optical Fiber Technology","volume":"96 ","pages":"Article 104473"},"PeriodicalIF":2.7,"publicationDate":"2025-11-05","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145475606","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 : 2025-11-05DOI: 10.1016/j.yofte.2025.104467
Xingling Peng , Zhipeng Gong , Hongfeng Shi , Mengdong Tang , Yiheng Li , Yingpeng Cha , Yulong Li
To address the degradation in wing shape reconstruction accuracy caused by the drift of fiber Bragg grating (FBG) sensing signals under dynamic force-thermal coupling conditions in aerospace applications, a novel wing shape reconstruction algorithm incorporating temperature compensation and strain correction is proposed. A wing curvature and displacement calculation model based on FBG temperature compensation and strain correction is constructed to achieve real-time compensation for temperature drift in FBG sensing signals, correction of strain transfer error, and decoupling of temperature, strain, curvature, and displacement. The temperature, strain, and displacement sensitivities of the carbon fiber composite wing model were calibrated via force/thermal loading tests. The curvature and wing tip displacement were obtained before and after temperature compensation. Combined with cubic spline curvature interpolation, coordinate transformation and B-spline surface reconstruction algorithm, the wing 3D surface shape reconstruction was completed. Test results indicate that without temperature compensation, the average relative error in wing tip displacement reconstruction reaches 8.75%. After real-time temperature compensation, this error is significantly reduced to 2.74%, with a deviation of only 0.72% from the finite element simulation benchmark error of 2.02%. This method significantly enhances the accuracy of wing shape reconstruction in force-thermal environments.
{"title":"Enhancing Wing Shape Reconstruction Precision in FBG Sensors Through Temperature Compensation and Strain Correction Mechanisms","authors":"Xingling Peng , Zhipeng Gong , Hongfeng Shi , Mengdong Tang , Yiheng Li , Yingpeng Cha , Yulong Li","doi":"10.1016/j.yofte.2025.104467","DOIUrl":"10.1016/j.yofte.2025.104467","url":null,"abstract":"<div><div>To address the degradation in wing shape reconstruction accuracy caused by the drift of fiber Bragg grating (FBG) sensing signals under dynamic force-thermal coupling conditions in aerospace applications, a novel wing shape reconstruction algorithm incorporating temperature compensation and strain correction is proposed. A wing curvature and displacement calculation model based on FBG temperature compensation and strain correction is constructed to achieve real-time compensation for temperature drift in FBG sensing signals, correction of strain transfer error, and decoupling of temperature, strain, curvature, and displacement. The temperature, strain, and displacement sensitivities of the carbon fiber composite wing model were calibrated via force/thermal loading tests. The curvature and wing tip displacement were obtained before and after temperature compensation. Combined with cubic spline curvature interpolation, coordinate transformation and B-spline surface reconstruction algorithm, the wing 3D surface shape reconstruction was completed. Test results indicate that without temperature compensation, the average relative error in wing tip displacement reconstruction reaches 8.75%. After real-time temperature compensation, this error is significantly reduced to 2.74%, with a deviation of only 0.72% from the finite element simulation benchmark error of 2.02%. This method significantly enhances the accuracy of wing shape reconstruction in force-thermal environments.</div></div>","PeriodicalId":19663,"journal":{"name":"Optical Fiber Technology","volume":"96 ","pages":"Article 104467"},"PeriodicalIF":2.7,"publicationDate":"2025-11-05","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145435401","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 : 2025-11-04DOI: 10.1016/j.yofte.2025.104468
Rizwan Aslam Butt , Saba Ahmed , Muhammad Imran Aslam , Sevia M. Idrus
The current PON standards do not support direct communication of the optical network units (ONUs) without the optical line terminal (OLT) intervention. This inter-ONU communication termed as IOC can be very helpful in conserving the upstream as well as the downstream bandwidth in current PON architectures. This approach can result in reduced communication delays and enables higher bandwidths to the users without increasing the upstream and downstream line rates. However, this requires physical layer architectural changes to enable IOC supported PON and also requires supporting medium access control (MAC) layer changes. Therefore, in this study, we propose a new MAC layer comprising of supporting upstream and downstream XGPON frames and a compatible dynamic bandwidth assignment (DBA) scheme for our earlier proposed IOC PON architecture. In our earlier work physical layer for an IOC PON comprising of single transmitter, self-phase modulation module and two receivers at ONU for downstream and IOC was presented. The OMNET++ based simulation study results show that the proposed architecture successfully reduced the upstream delays and resulted in higher bandwidth availability for the ONUs compared to conventional PON.
目前的PON标准不支持光网络单元（onu）在没有OLT （optical line terminal）介入的情况下直接通信。在当前的PON架构中，这种称为IOC的onu间通信对于节约上游和下游带宽非常有帮助。这种方法可以减少通信延迟，在不增加上行和下行线路速率的情况下为用户提供更高的带宽。但是，这需要更改物理层体系结构以启用IOC支持的PON，还需要更改介质访问控制（MAC）层。因此，在本研究中，我们提出了一个新的MAC层，包括支持上游和下游XGPON帧和兼容的动态带宽分配（DBA）方案，用于我们之前提出的IOC PON架构。在我们早期的工作中，提出了由单个发射机、自相位调制模块和两个ONU接收器组成的IOC PON的物理层，用于下游和IOC。基于omnet++的仿真研究结果表明，与传统的PON相比，该架构成功地降低了上游延迟，并为onu提供了更高的带宽可用性。
{"title":"IOC supported dynamic bandwidth assignment for ITU PONs","authors":"Rizwan Aslam Butt , Saba Ahmed , Muhammad Imran Aslam , Sevia M. Idrus","doi":"10.1016/j.yofte.2025.104468","DOIUrl":"10.1016/j.yofte.2025.104468","url":null,"abstract":"<div><div>The current PON standards do not support direct communication of the optical network units (ONUs) without the optical line terminal (OLT) intervention. This inter-ONU communication termed as IOC can be very helpful in conserving the upstream as well as the downstream bandwidth in current PON architectures. This approach can result in reduced communication delays and enables higher bandwidths to the users without increasing the upstream and downstream line rates. However, this requires physical layer architectural changes to enable IOC supported PON and also requires supporting medium access control (MAC) layer changes. Therefore, in this study, we propose a new MAC layer comprising of supporting upstream and downstream XGPON frames and a compatible dynamic bandwidth assignment (DBA) scheme for our earlier proposed IOC PON architecture. In our earlier work physical layer for an IOC PON comprising of single transmitter, self-phase modulation module and two receivers at ONU for downstream and IOC was presented. The OMNET++ based simulation study results show that the proposed architecture successfully reduced the upstream delays and resulted in higher bandwidth availability for the ONUs compared to conventional PON.</div></div>","PeriodicalId":19663,"journal":{"name":"Optical Fiber Technology","volume":"96 ","pages":"Article 104468"},"PeriodicalIF":2.7,"publicationDate":"2025-11-04","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145435399","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 : 2025-11-04DOI: 10.1016/j.yofte.2025.104471
Arno Klenke , Cesar Jauregui , Mehran Bahri , Johannes Nold , Stefan Kuhn , Nicoletta Haarlammert , Thomas Schreiber , Jens Limpert
Fiber lasers are nowadays one of the preferred coherent light sources when high average powers up to the multi-kW regime are targeted. Additionally, they are also widely employed for the generation of ultrashort pulses with moderate energy in the mJ-range. However, numerous physical limitations currently hinder a further performance scaling. One way to overcome these limitations is the coherent beam combination of parallel amplifiers. This approach has led to laser systems operating beyond the limits of a single amplifier, albeit at the cost of an increase in footprint and complexity. Amplifying multicore fibers hold the promise to combine the simplicity of fiber lasers with unprecedented performance scaling prospects and the additional benefit of enabling dynamic beam and pulse shaping. In this paper, basic considerations about design parameters of multicore fibers with non-coupling cores are given and the impact of physical effects on the output emission is discussed. State-of-the art results of multicore-fiber-based laser systems are reviewed with these fibers now being able to output kW-level average powers and nanosecond pulses with over 100 mJ pulse energies. Finally, an outlook regarding future performance targets and possible applications is given.
{"title":"High-power ytterbium-doped multicore fibers","authors":"Arno Klenke , Cesar Jauregui , Mehran Bahri , Johannes Nold , Stefan Kuhn , Nicoletta Haarlammert , Thomas Schreiber , Jens Limpert","doi":"10.1016/j.yofte.2025.104471","DOIUrl":"10.1016/j.yofte.2025.104471","url":null,"abstract":"<div><div>Fiber lasers are nowadays one of the preferred coherent light sources when high average powers up to the multi-kW regime are targeted. Additionally, they are also widely employed for the generation of ultrashort pulses with moderate energy in the mJ-range. However, numerous physical limitations currently hinder a further performance scaling. One way to overcome these limitations is the coherent beam combination of parallel amplifiers. This approach has led to laser systems operating beyond the limits of a single amplifier, albeit at the cost of an increase in footprint and complexity. Amplifying multicore fibers hold the promise to combine the simplicity of fiber lasers with unprecedented performance scaling prospects and the additional benefit of enabling dynamic beam and pulse shaping. In this paper, basic considerations about design parameters of multicore fibers with non-coupling cores are given and the impact of physical effects on the output emission is discussed. State-of-the art results of multicore-fiber-based laser systems are reviewed with these fibers now being able to output kW-level average powers and nanosecond pulses with over 100 mJ pulse energies. Finally, an outlook regarding future performance targets and possible applications is given.</div></div>","PeriodicalId":19663,"journal":{"name":"Optical Fiber Technology","volume":"96 ","pages":"Article 104471"},"PeriodicalIF":2.7,"publicationDate":"2025-11-04","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145435400","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 : 2025-11-03DOI: 10.1016/j.yofte.2025.104461
Alexey Kuznetsov, Alexander Dostovalov, Evgeniy Podivilov, Sergey Babin
Femtosecond inscription of fiber Bragg gratings (FBGs) in each core of a cladding-pumped 2-core Yb-doped fiber at the shifted Bragg wavelengths offers generation of two laser lines simultaneously if the cores are not optically coupled, at that the laser lines follow the FBG reflection maxima in corresponding cores. If the cores become strongly coupled at coiling the fiber with 6 cm diameter, the laser starts to generate single peak located in the overlap area of the shifted FBGs that is why it is sufficiently narrower than the net spectrum of independent generation. The spectrum collapse effect is observed up to the FBG shift value as large as ∼ 0.47 nm (nearly twice of the individual FBG bandwidth of ∼ 0.25 nm), when the central peak corresponds to the overlap between FBG side lobes. It is unstable but becomes more stable and dominating at increasing power. It is shown that the generated spectrum shape corresponds to the geometric mean of individual FBG spectra in all cases, in correspondence with the developed model. The obtained results offer new opportunities for the output laser line shaping and extreme narrowing with the use of conventional FBGs.
{"title":"Generation spectrum of a 2-core fiber laser with wavelength-shifted FBG cavity","authors":"Alexey Kuznetsov, Alexander Dostovalov, Evgeniy Podivilov, Sergey Babin","doi":"10.1016/j.yofte.2025.104461","DOIUrl":"10.1016/j.yofte.2025.104461","url":null,"abstract":"<div><div>Femtosecond inscription of fiber Bragg gratings (FBGs) in each core of a cladding-pumped 2-core Yb-doped fiber at the shifted Bragg wavelengths offers generation of two laser lines simultaneously if the cores are not optically coupled, at that the laser lines follow the FBG reflection maxima in corresponding cores. If the cores become strongly coupled at coiling the fiber with 6 cm diameter, the laser starts to generate single peak located in the overlap area of the shifted FBGs that is why it is sufficiently narrower than the net spectrum of independent generation. The spectrum collapse effect is observed up to the FBG shift value as large as ∼ 0.47 nm (nearly twice of the individual FBG bandwidth of ∼ 0.25 nm), when the central peak corresponds to the overlap between FBG side lobes. It is unstable but becomes more stable and dominating at increasing power. It is shown that the generated spectrum shape corresponds to the geometric mean of individual FBG spectra in all cases, in correspondence with the developed model. The obtained results offer new opportunities for the output laser line shaping and extreme narrowing with the use of conventional FBGs.</div></div>","PeriodicalId":19663,"journal":{"name":"Optical Fiber Technology","volume":"95 ","pages":"Article 104461"},"PeriodicalIF":2.7,"publicationDate":"2025-11-03","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145465820","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 : 2025-11-03DOI: 10.1016/j.yofte.2025.104462
Fatma Ebrahim Mohamed Elnady , Ibrahim S. Tarrad , Khalid F.A. Hussein , Mohamed Yasin I. Afifi
Understanding the longitudinal strain distribution and its gradient is vital in a wide range of applications, from ensuring the structural integrity of components such as beams and plates to analyzing high-frequency mechanical systems where longitudinal strain gradients influence the propagation of stress waves through materials. Moreover, it plays a significant role in biomedical applications, such as examining strain gradients in elongated biological tissues like tendons and ligaments essential for understanding tissue mechanics and designing effective interventions. This work proposes a novel strain gradient sensor based on fiber Bragg grating (FBG) technology. The sensor comprises cascaded uniform FBGs (UFBGs) uniformly distributed along the wire-under-test (WUT) to measure the applied strain along its length. An accurate analytical model has been developed to describe the sensor’s operation and evaluate its performance. Numerical results are presented, focusing on accuracy, demonstrating the enhanced performance of the proposed strain gradient sensor. Using 11 cascaded UFBGs, the effects of number of grating periods (), AC coupling coefficient between the two modes (K), separation between the Bragg wavelength of consecutive UFBGs (, and thermal noise on system accuracy were investigated. It was discovered that while increasing K and N improves sensor accuracy, increasing ( and thermal noise has a trade-off that lowers sensor accuracy. Depending on the application, these trade-offs may be taken into consideration.
{"title":"Strain gradient sensor with high accuracy using cascaded fiber Bragg gratings","authors":"Fatma Ebrahim Mohamed Elnady , Ibrahim S. Tarrad , Khalid F.A. Hussein , Mohamed Yasin I. Afifi","doi":"10.1016/j.yofte.2025.104462","DOIUrl":"10.1016/j.yofte.2025.104462","url":null,"abstract":"<div><div>Understanding the longitudinal strain distribution and its gradient is vital in a wide range of applications, from ensuring the structural integrity of components such as beams and plates to analyzing high-frequency mechanical systems where longitudinal strain gradients influence the propagation of stress waves through materials. Moreover, it plays a significant role in biomedical applications, such as examining strain gradients in elongated biological tissues like tendons and ligaments essential for understanding tissue mechanics and designing effective interventions. This work proposes a novel strain gradient sensor based on fiber Bragg grating (FBG) technology. The sensor comprises <span><math><mi>M</mi></math></span> cascaded uniform FBGs (UFBGs) uniformly distributed along the wire-under-test (WUT) to measure the applied strain along its length. An accurate analytical model has been developed to describe the sensor’s operation and evaluate its performance. Numerical results are presented, focusing on accuracy, demonstrating the enhanced performance of the proposed strain gradient sensor. Using 11 cascaded UFBGs, the effects of number of grating periods (<span><math><mi>N</mi></math></span>), AC coupling coefficient between the two modes (K), separation between the Bragg wavelength of consecutive UFBGs (<span><math><mrow><msub><mrow><mi>D</mi><mi>λ</mi></mrow><mi>B</mi></msub><mrow><mo>)</mo></mrow></mrow></math></span>, and thermal noise on system accuracy were investigated. It was discovered that while increasing K and N improves sensor accuracy, increasing (<span><math><mrow><msub><mrow><mi>D</mi><mi>λ</mi></mrow><mi>B</mi></msub><mrow><mo>)</mo></mrow></mrow></math></span> and thermal noise has a trade-off that lowers sensor accuracy. Depending on the application, these trade-offs may be taken into consideration.</div></div>","PeriodicalId":19663,"journal":{"name":"Optical Fiber Technology","volume":"95 ","pages":"Article 104462"},"PeriodicalIF":2.7,"publicationDate":"2025-11-03","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145465822","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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