We present a Nd:Gd3Sc2Al3O12(Nd:GSAG) laser operating at three wavelengths via the 4F3/2 → 4I13/2 transition. The gain-to-loss balance condition for simultaneous triple-wavelength operation was analyzed numerically using a birefringent filter (BRF). Experimentally, a continuous-wave (CW) emission at 1402 nm, 1426 nm and 1440 nm was demonstrated. Under an incident pump power of 20 W at 808 nm, the laser obtained a maximum total output power of 2.23 W, corresponding to an optical-to-optical conversion efficiency of 11.2%. To the best of our knowledge, this study theoretically establishes, for the first time, the equal-threshold condition for simultaneous operation of a triple-wavelength laser using a single loss element.
{"title":"Simultaneous Triple-Wavelength Operation of a Diode-Pumped Nd: GSAG Laser at 1.4 μm","authors":"Haotian Huang;Jing Xia;Rui Yang;Nguyentuan Anh;Yuzhao Li;Yanfei Lü","doi":"10.1109/LPT.2026.3669098","DOIUrl":"https://doi.org/10.1109/LPT.2026.3669098","url":null,"abstract":"We present a Nd:Gd3Sc2Al3O12(Nd:GSAG) laser operating at three wavelengths via the 4F3/2 → 4I13/2 transition. The gain-to-loss balance condition for simultaneous triple-wavelength operation was analyzed numerically using a birefringent filter (BRF). Experimentally, a continuous-wave (CW) emission at 1402 nm, 1426 nm and 1440 nm was demonstrated. Under an incident pump power of 20 W at 808 nm, the laser obtained a maximum total output power of 2.23 W, corresponding to an optical-to-optical conversion efficiency of 11.2%. To the best of our knowledge, this study theoretically establishes, for the first time, the equal-threshold condition for simultaneous operation of a triple-wavelength laser using a single loss element.","PeriodicalId":13065,"journal":{"name":"IEEE Photonics Technology Letters","volume":"38 11","pages":"755-758"},"PeriodicalIF":2.5,"publicationDate":"2026-03-02","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"147362308","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Tin resonators can confine the coupled electromagnetic dipolar field. The interaction of patterned Tin based ultrathin metasurface to optical wave can provide the incident angle dependent multiband resonances offering narrow line-shape optical absorption in visible range. The proposed metasurface can provide a high modulation sensitivity for incident angle. Moreover, the proposed metasurface can provide the Brewster controlled resonances in different plane of polarization of the incident optical wave. Numerical study shows that proposed metasurface can be utilized for refractive index sensing and in the detection of air-borne pathogenic viruses, and blood, cervical and skin cancer.
{"title":"Angle Multiplexed Brewster Controlled Multiband Absorber for Optical Sensing","authors":"Parvendra Kumar;Gaurav Varshney;Pushpa Giri;Shivendra Kumar Jaiswal","doi":"10.1109/LPT.2026.3669218","DOIUrl":"https://doi.org/10.1109/LPT.2026.3669218","url":null,"abstract":"Tin resonators can confine the coupled electromagnetic dipolar field. The interaction of patterned Tin based ultrathin metasurface to optical wave can provide the incident angle dependent multiband resonances offering narrow line-shape optical absorption in visible range. The proposed metasurface can provide a high modulation sensitivity for incident angle. Moreover, the proposed metasurface can provide the Brewster controlled resonances in different plane of polarization of the incident optical wave. Numerical study shows that proposed metasurface can be utilized for refractive index sensing and in the detection of air-borne pathogenic viruses, and blood, cervical and skin cancer.","PeriodicalId":13065,"journal":{"name":"IEEE Photonics Technology Letters","volume":"38 11","pages":"767-770"},"PeriodicalIF":2.5,"publicationDate":"2026-03-02","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"147440557","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"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 : 2026-03-02DOI: 10.1109/LPT.2026.3669735
Yuhuai Huang;Xiaopeng Dong;Peichao Chen
Conventional vibration demodulation typically utilizes nearby sample points in conjunction with pulses having relatively wide width for demodulation, which has drawbacks, including inconsistent spatial positions corresponding to adjacent sampling points and limited spatial resolution. This research proposes a novel quantitative vibration demodulation technique based on direct detection $Phi $ -OTDR to address this issue. At a set repetition frequency, this technique alternately emits optical pulses with comparable but different pulse lengths. To precisely demodulate the vibration phase, it obtains two optical intensity signals at the same fiber position, which have different initial phases but virtually similar vibration-induced phase shifts. Compared with the conventional demodulation method, the proposed technique achieves a signal-to-noise ratio (SNR) improvement of 9.4 dB. By not relying on the data acquisition card’s (DAQ) sampling rate, this technique reduces the acquisition system’s cost and performance requirements while avoiding the spatial resolution deterioration associated with conventional demodulation using nearby sampling points.
{"title":"Direct Detection Φ-OTDR System Based on the Different Pulse Width Method","authors":"Yuhuai Huang;Xiaopeng Dong;Peichao Chen","doi":"10.1109/LPT.2026.3669735","DOIUrl":"https://doi.org/10.1109/LPT.2026.3669735","url":null,"abstract":"Conventional vibration demodulation typically utilizes nearby sample points in conjunction with pulses having relatively wide width for demodulation, which has drawbacks, including inconsistent spatial positions corresponding to adjacent sampling points and limited spatial resolution. This research proposes a novel quantitative vibration demodulation technique based on direct detection <inline-formula> <tex-math>$Phi $ </tex-math></inline-formula>-OTDR to address this issue. At a set repetition frequency, this technique alternately emits optical pulses with comparable but different pulse lengths. To precisely demodulate the vibration phase, it obtains two optical intensity signals at the same fiber position, which have different initial phases but virtually similar vibration-induced phase shifts. Compared with the conventional demodulation method, the proposed technique achieves a signal-to-noise ratio (SNR) improvement of 9.4 dB. By not relying on the data acquisition card’s (DAQ) sampling rate, this technique reduces the acquisition system’s cost and performance requirements while avoiding the spatial resolution deterioration associated with conventional demodulation using nearby sampling points.","PeriodicalId":13065,"journal":{"name":"IEEE Photonics Technology Letters","volume":"38 11","pages":"771-774"},"PeriodicalIF":2.5,"publicationDate":"2026-03-02","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"147440680","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Optical switch plays an important role in the modern optical communication. In this letter, we demonstrate an O band $8times 8$ switch array based on 2% $Delta $ silica platform. The $8times 8$ switch array is designed with BENES topology having 20 balanced Mach–Zehnder interferometer based switch elements. At 1310 nm, the switch shows good performance. The on-chip loss is lower than 1.18 dB and the crosstalk is better than −16.32 dB. The rise time (10%-90%) and fall time (90%-10%) of the switch are both 1.3 ms at 1310 nm. The transmission experiments of 10 Gbps on-off keying are successfully realized.
{"title":"O-Band TO Optical Switch Based on Silica Platform","authors":"Minghui Zhou;Yuexin Yin;Guoyan Zeng;Xinru Xu;Daming Zhang","doi":"10.1109/LPT.2026.3669087","DOIUrl":"https://doi.org/10.1109/LPT.2026.3669087","url":null,"abstract":"Optical switch plays an important role in the modern optical communication. In this letter, we demonstrate an O band <inline-formula> <tex-math>$8times 8$ </tex-math></inline-formula> switch array based on 2% <inline-formula> <tex-math>$Delta $ </tex-math></inline-formula> silica platform. The <inline-formula> <tex-math>$8times 8$ </tex-math></inline-formula> switch array is designed with BENES topology having 20 balanced Mach–Zehnder interferometer based switch elements. At 1310 nm, the switch shows good performance. The on-chip loss is lower than 1.18 dB and the crosstalk is better than −16.32 dB. The rise time (10%-90%) and fall time (90%-10%) of the switch are both 1.3 ms at 1310 nm. The transmission experiments of 10 Gbps on-off keying are successfully realized.","PeriodicalId":13065,"journal":{"name":"IEEE Photonics Technology Letters","volume":"38 11","pages":"743-746"},"PeriodicalIF":2.5,"publicationDate":"2026-02-27","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"147362310","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"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 : 2026-02-23DOI: 10.1109/LPT.2026.3666869
Kai Zhang;Hongwei Li;Youxing Li;Tingting Yuan;Xiaotong Zhang;Libo Yuan
We have constructed an integrated optical fiber tweezers (OFTs) platform based on double-core fibers (DCF) and Coreless fiber (CF), which is designed for trapping multiple particles. In this configuration, the DCF-guided LP01 mode generates two mirror-symmetric Bessel-like beams within the CF. These beams form multiple independent optical potential well arrays at the end face of the CF. Using this OTFs, we successfully achieved stable trapping of three yeast cells. Furthermore, through precise optical power control, we demonstrated the trapping and dynamic rearrangement of three yeast cells.
{"title":"Particle Manipulation Based on Multiple Optical Potential Wells Using Optical Fiber Tweezers","authors":"Kai Zhang;Hongwei Li;Youxing Li;Tingting Yuan;Xiaotong Zhang;Libo Yuan","doi":"10.1109/LPT.2026.3666869","DOIUrl":"https://doi.org/10.1109/LPT.2026.3666869","url":null,"abstract":"We have constructed an integrated optical fiber tweezers (OFTs) platform based on double-core fibers (DCF) and Coreless fiber (CF), which is designed for trapping multiple particles. In this configuration, the DCF-guided LP01 mode generates two mirror-symmetric Bessel-like beams within the CF. These beams form multiple independent optical potential well arrays at the end face of the CF. Using this OTFs, we successfully achieved stable trapping of three yeast cells. Furthermore, through precise optical power control, we demonstrated the trapping and dynamic rearrangement of three yeast cells.","PeriodicalId":13065,"journal":{"name":"IEEE Photonics Technology Letters","volume":"38 11","pages":"723-726"},"PeriodicalIF":2.5,"publicationDate":"2026-02-23","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"147299658","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"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 : 2026-02-23DOI: 10.1109/LPT.2026.3666897
Hui Liu;Xinze Rao;Tian Zhang;Jian Dai;Kun Xu
We demonstrate a reconfigurable all-fiber femtosecond source with tunable repetition rates from 100 MHz to 1 GHz. The system establishes a rigid 1 GHz time grid via a dispersion-managed passive interleaver, followed by self-synchronized steep-edge electro-optic gating (rise time <40 ps) to temporally decouple switching noise from the signal. This architecture achieves arbitrary pulse picking with single-pulse granularity while experimentally preserving the seed’s intrinsic stability. Hybrid phase noise measurements confirm an integrated RMS timing jitter below 10 fs [1 kHz–1 MHz] and a 38.4 dB extinction ratio. This versatile platform provides oscillator-limited timing fidelity for arbitrary pulse patterns, offering a robust tool for precision-driven applications such as high-speed sampling systems and time-resolved biological imaging.
{"title":"A Reconfigurable All-Fiber Femtosecond Source With Low Jitter and Programmable Pulse Picking","authors":"Hui Liu;Xinze Rao;Tian Zhang;Jian Dai;Kun Xu","doi":"10.1109/LPT.2026.3666897","DOIUrl":"https://doi.org/10.1109/LPT.2026.3666897","url":null,"abstract":"We demonstrate a reconfigurable all-fiber femtosecond source with tunable repetition rates from 100 MHz to 1 GHz. The system establishes a rigid 1 GHz time grid via a dispersion-managed passive interleaver, followed by self-synchronized steep-edge electro-optic gating (rise time <40 ps) to temporally decouple switching noise from the signal. This architecture achieves arbitrary pulse picking with single-pulse granularity while experimentally preserving the seed’s intrinsic stability. Hybrid phase noise measurements confirm an integrated RMS timing jitter below 10 fs [1 kHz–1 MHz] and a 38.4 dB extinction ratio. This versatile platform provides oscillator-limited timing fidelity for arbitrary pulse patterns, offering a robust tool for precision-driven applications such as high-speed sampling systems and time-resolved biological imaging.","PeriodicalId":13065,"journal":{"name":"IEEE Photonics Technology Letters","volume":"38 11","pages":"775-778"},"PeriodicalIF":2.5,"publicationDate":"2026-02-23","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"147440689","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"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 : 2026-02-23DOI: 10.1109/LPT.2026.3666808
Kai Li;Zhang Chen;Renjing Xu;Renjie Wang
The design of nanophotonic devices (e.g., metasurfaces) is computationally demanding due to time-consuming electromagnetic simulations. Here, we propose an end-to-end bidirectional design framework integrating a deep learning surrogate model with differential evolution algorithm for all-dielectric metasurfaces exhibiting Fano resonance. Firstly, a multipole decomposition analysis is conducted to reveal the dominance of magnetic dipole and toroidal dipole at the resonance wavelengths, elucidating potential physical mechanisms. Then, a surrogate model trained with finite-difference time-domain (FDTD) data achieves millisecond-level reflectance spectrum prediction with 4.46% average error (99.55% similarity to FDTD), achieving a 38,$000times $ speedup. Finally, integrated with differential evolution algorithm, it enables inverse design of user-defined spectral features within 10 seconds. This work will promote the design and optimization of high-dimensional parameters, accelerate the inverse design of complex metasurfaces, and reduce trial-and-error costs.
{"title":"A Hybrid Neural-Evolutionary Design Framework of All-Dielectric Magnetic-Toroidal Fano Metasurfaces","authors":"Kai Li;Zhang Chen;Renjing Xu;Renjie Wang","doi":"10.1109/LPT.2026.3666808","DOIUrl":"https://doi.org/10.1109/LPT.2026.3666808","url":null,"abstract":"The design of nanophotonic devices (e.g., metasurfaces) is computationally demanding due to time-consuming electromagnetic simulations. Here, we propose an end-to-end bidirectional design framework integrating a deep learning surrogate model with differential evolution algorithm for all-dielectric metasurfaces exhibiting Fano resonance. Firstly, a multipole decomposition analysis is conducted to reveal the dominance of magnetic dipole and toroidal dipole at the resonance wavelengths, elucidating potential physical mechanisms. Then, a surrogate model trained with finite-difference time-domain (FDTD) data achieves millisecond-level reflectance spectrum prediction with 4.46% average error (99.55% similarity to FDTD), achieving a 38,<inline-formula> <tex-math>$000times $ </tex-math></inline-formula> speedup. Finally, integrated with differential evolution algorithm, it enables inverse design of user-defined spectral features within 10 seconds. This work will promote the design and optimization of high-dimensional parameters, accelerate the inverse design of complex metasurfaces, and reduce trial-and-error costs.","PeriodicalId":13065,"journal":{"name":"IEEE Photonics Technology Letters","volume":"38 11","pages":"735-738"},"PeriodicalIF":2.5,"publicationDate":"2026-02-23","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"147362305","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"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 : 2026-02-23DOI: 10.1109/LPT.2026.3667083
Shasha Liao;Wenjia Xie;Xingchen Fan
Rectangular filters are widely employed in diverse fields, including communications, sensing, and healthcare. We propose and demonstrate an ultra-compact rectangular filter with high shape factor tunable local edge steepness. By utilizing a single microring resonator embedded with a slot, the slot-induced reflection of optical signals enables the rectangular filtering response. The filter occupies a core area of less than $900~mu $ m2 and achieves a shape factor (SF, 10-dB bandwidth/3-dB bandwidth) of 1.59. By thermal tuning the heaters in the filter, the local edge steepness near the 10-dB, 15-dB, and 20-dB bandwidths becomes adjustable. Our filter combines advantages such as compact footprint, remarkable SF, and fabrication simplicity. Moreover, its controllable edge steepness offers unique potential for applications in mid-infrared gas absorption spectroscopy, medical imaging, and laser ranging.
{"title":"An Ultra-Compact Rectangular Filter Featuring Optimized Local Edge Steepness","authors":"Shasha Liao;Wenjia Xie;Xingchen Fan","doi":"10.1109/LPT.2026.3667083","DOIUrl":"https://doi.org/10.1109/LPT.2026.3667083","url":null,"abstract":"Rectangular filters are widely employed in diverse fields, including communications, sensing, and healthcare. We propose and demonstrate an ultra-compact rectangular filter with high shape factor tunable local edge steepness. By utilizing a single microring resonator embedded with a slot, the slot-induced reflection of optical signals enables the rectangular filtering response. The filter occupies a core area of less than <inline-formula> <tex-math>$900~mu $ </tex-math></inline-formula>m2 and achieves a shape factor (SF, 10-dB bandwidth/3-dB bandwidth) of 1.59. By thermal tuning the heaters in the filter, the local edge steepness near the 10-dB, 15-dB, and 20-dB bandwidths becomes adjustable. Our filter combines advantages such as compact footprint, remarkable SF, and fabrication simplicity. Moreover, its controllable edge steepness offers unique potential for applications in mid-infrared gas absorption spectroscopy, medical imaging, and laser ranging.","PeriodicalId":13065,"journal":{"name":"IEEE Photonics Technology Letters","volume":"38 11","pages":"719-722"},"PeriodicalIF":2.5,"publicationDate":"2026-02-23","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"147299661","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
This letter presents a refractive index (RI) fiber sensor based on chirped waveguide broadening by expanding and shrinking the core diameter of multi-mode fibers (MMFs) in the no-core fibers (NCFs). Embedding of MMFs with different core diameter in the NCF enables redistributed optical power from the fundamental core mode to cladding modes, thereby efficiently exciting cladding modes. The experimental results show that in the RI range of 1.33 to 1.42, the sensitivities of Dip A (1450 nm), Dip B (1550 nm), and Dip C (1650 nm) are 568.56 nm/RIU, 851.29 nm/RIU, and 580.91 nm/RIU, respectively. The proposed sensor has the characteristics of high mechanical strength and low temperature crosstalk. It is expected to be used in the fields of environmental monitoring and concentration identification, etc.
本文提出了一种基于啁啾波导展宽的折射率（RI）光纤传感器，该传感器通过扩大和缩小无芯光纤（nfc）中的多模光纤（MMFs）的芯径。在NCF中嵌入不同芯径的MMFs，可以将光功率从基芯模式重新分配到包层模式，从而有效地激发包层模式。实验结果表明，在1.33 ~ 1.42的RI范围内，Dip A （1450 nm）、Dip B （1550 nm）和Dip C （1650 nm）的灵敏度分别为568.56 nm/RIU、851.29 nm/RIU和580.91 nm/RIU。该传感器具有高机械强度和低温串扰的特点。有望在环境监测、浓度识别等领域得到应用。
{"title":"Sensitivity-Enhanced Refractometer Based on Periodic Chirped Waveguide Broadening","authors":"Qianfei Zhu;Xiao Li;Tian Tian;Ze Yu;Dongqing Zhao;Yiwei Ma;Yongtian Zhu;Tao Geng","doi":"10.1109/LPT.2026.3666343","DOIUrl":"https://doi.org/10.1109/LPT.2026.3666343","url":null,"abstract":"This letter presents a refractive index (RI) fiber sensor based on chirped waveguide broadening by expanding and shrinking the core diameter of multi-mode fibers (MMFs) in the no-core fibers (NCFs). Embedding of MMFs with different core diameter in the NCF enables redistributed optical power from the fundamental core mode to cladding modes, thereby efficiently exciting cladding modes. The experimental results show that in the RI range of 1.33 to 1.42, the sensitivities of Dip A (1450 nm), Dip B (1550 nm), and Dip C (1650 nm) are 568.56 nm/RIU, 851.29 nm/RIU, and 580.91 nm/RIU, respectively. The proposed sensor has the characteristics of high mechanical strength and low temperature crosstalk. It is expected to be used in the fields of environmental monitoring and concentration identification, etc.","PeriodicalId":13065,"journal":{"name":"IEEE Photonics Technology Letters","volume":"38 11","pages":"763-766"},"PeriodicalIF":2.5,"publicationDate":"2026-02-19","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"147440686","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"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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