Pub Date : 2025-11-04DOI: 10.1109/LPT.2025.3628742
Junjie Mao;Yangyang Wang;Kuo Hua;Changyu Shen;Chen Liu
An accurate dispersion measurement approach for chirped fiber Bragg gratings (CFBGs) based on a wavelength-tunable mode-locked fiber laser is proposed and demonstrated. The relationship between group delay and the mode-locked laser’s repetition rate is analytically derived. Dispersion information and the tunning ranges of $2^{mathbf {nd}}$ and $3^{mathbf {rd}}$ dispersion coefficients of a commercial tunable CFBG are determined experimentally, which are agree well with the specifications provided by the manufacturer. Compared with other techniques, the proposed method is straightforward to operate. The retrieved high-order dispersion information of CFBGs will be greatly benefit to the fiber chirped-pulse amplification system and ultrafast laser techniques.
{"title":"Dispersion Measurement of Chirped Fiber Bragg Grating Using a Tunable Mode-Locked Laser","authors":"Junjie Mao;Yangyang Wang;Kuo Hua;Changyu Shen;Chen Liu","doi":"10.1109/LPT.2025.3628742","DOIUrl":"https://doi.org/10.1109/LPT.2025.3628742","url":null,"abstract":"An accurate dispersion measurement approach for chirped fiber Bragg gratings (CFBGs) based on a wavelength-tunable mode-locked fiber laser is proposed and demonstrated. The relationship between group delay and the mode-locked laser’s repetition rate is analytically derived. Dispersion information and the tunning ranges of <inline-formula> <tex-math>$2^{mathbf {nd}}$ </tex-math></inline-formula> and <inline-formula> <tex-math>$3^{mathbf {rd}}$ </tex-math></inline-formula> dispersion coefficients of a commercial tunable CFBG are determined experimentally, which are agree well with the specifications provided by the manufacturer. Compared with other techniques, the proposed method is straightforward to operate. The retrieved high-order dispersion information of CFBGs will be greatly benefit to the fiber chirped-pulse amplification system and ultrafast laser techniques.","PeriodicalId":13065,"journal":{"name":"IEEE Photonics Technology Letters","volume":"38 4","pages":"239-242"},"PeriodicalIF":2.5,"publicationDate":"2025-11-04","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145500520","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 : 2025-11-03DOI: 10.1109/LPT.2025.3627909
Jie Li;Yongqi Ye;Daixn Lian;Shi Zhao;Jingye Chen;Yaocheng Shi
A high-performance lithium niobate TM-pass polarizer is proposed and demonstrated experimentally. It is based on polymer-loaded lithium niobate on an insulator (LNOI) platform harnessing bound states in the continuum. In polymer-LNOI ridge waveguides, the TM polarization wave will undergo mode leakage, of which the intensity depends on the width and radius of ridge waveguides. Bound states in the continuum points are formed when the waveguide satisfies certain ridge width and radius conditions, leading to suppression of leakage loss. An extremely high extinction ratio can be achieved by leaking the TE light in the slab using a bent waveguide. The 3D FDTD simulations show a TM loss of less than 0.4 dB and an extinction ratio greater than 34 dB over a 100 nm wavelength range from 1500 to 1600 nm. The measured insertion loss is <0.8>20 dB) over 70 nm wavelength range (1530 to 1600 nm).
{"title":"Etchless Lithium Niobate TM-Pass Polarizer Based on Bound States in the Continuum","authors":"Jie Li;Yongqi Ye;Daixn Lian;Shi Zhao;Jingye Chen;Yaocheng Shi","doi":"10.1109/LPT.2025.3627909","DOIUrl":"https://doi.org/10.1109/LPT.2025.3627909","url":null,"abstract":"A high-performance lithium niobate TM-pass polarizer is proposed and demonstrated experimentally. It is based on polymer-loaded lithium niobate on an insulator (LNOI) platform harnessing bound states in the continuum. In polymer-LNOI ridge waveguides, the TM polarization wave will undergo mode leakage, of which the intensity depends on the width and radius of ridge waveguides. Bound states in the continuum points are formed when the waveguide satisfies certain ridge width and radius conditions, leading to suppression of leakage loss. An extremely high extinction ratio can be achieved by leaking the TE light in the slab using a bent waveguide. The 3D FDTD simulations show a TM loss of less than 0.4 dB and an extinction ratio greater than 34 dB over a 100 nm wavelength range from 1500 to 1600 nm. The measured insertion loss is <0.8>20 dB) over 70 nm wavelength range (1530 to 1600 nm).","PeriodicalId":13065,"journal":{"name":"IEEE Photonics Technology Letters","volume":"38 4","pages":"223-226"},"PeriodicalIF":2.5,"publicationDate":"2025-11-03","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145500486","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 : 2025-11-03DOI: 10.1109/LPT.2025.3628068
Natalia V. Kryzhanovskaya;Sergey D. Komarov;Eduard I. Moiseev;Konstantin A. Ivanov;Dmitry A. Masyutin;Ivan S. Makhov;Andrey F. Tsatsul'nikov;Alexey V. Sakharov;Dmitry S. Arteev;Evgenii V. Lutsenko;Aliaksei G. Vainilovich;Andrey E. Nikolaev;Evgeniy E. Zavarin;Antonina A. Pivovarova;Natalia D. Il'inskaya;Irina P. Smirnova;Lev K. Markov;Nikolay Cherkashin;Alexey E. Zhukov
III-N ring microlasers on a silicon substrate with InGaN/GaN active layers emitting near 420 nm were investigated. The growth conditions and fabrication steps were optimized to realize stable lasing under optical pumping in cavities with a diameter of 6-$10~mu $ m. Chemically sensitive transmission electron microscopy images indicate that InGaN layers present in form of isolated islands. Between these InGaN islands, large areas of GaN are visible, forming barriers to lateral transport of free charge carriers in the active region and preventing their nonradiative surface recombination. For the first time, temperature stability of InGaN/GaN microring lasers characteristics are studied and lasing up to 100 degrees Celsius is demonstrated with the wavelength shift less than 1 nm. At room temperature, the threshold pump power is as low as 220 kW/cm${}^{mathbf {2}}$ . The obtained results significantly expand the potential areas of application of III-N microlasers.
{"title":"High Temperature Operation and Spectral Stability of InGaN/GaN Ring Microlasers on Silicon","authors":"Natalia V. Kryzhanovskaya;Sergey D. Komarov;Eduard I. Moiseev;Konstantin A. Ivanov;Dmitry A. Masyutin;Ivan S. Makhov;Andrey F. Tsatsul'nikov;Alexey V. Sakharov;Dmitry S. Arteev;Evgenii V. Lutsenko;Aliaksei G. Vainilovich;Andrey E. Nikolaev;Evgeniy E. Zavarin;Antonina A. Pivovarova;Natalia D. Il'inskaya;Irina P. Smirnova;Lev K. Markov;Nikolay Cherkashin;Alexey E. Zhukov","doi":"10.1109/LPT.2025.3628068","DOIUrl":"https://doi.org/10.1109/LPT.2025.3628068","url":null,"abstract":"III-N ring microlasers on a silicon substrate with InGaN/GaN active layers emitting near 420 nm were investigated. The growth conditions and fabrication steps were optimized to realize stable lasing under optical pumping in cavities with a diameter of 6-<inline-formula> <tex-math>$10~mu $ </tex-math></inline-formula>m. Chemically sensitive transmission electron microscopy images indicate that InGaN layers present in form of isolated islands. Between these InGaN islands, large areas of GaN are visible, forming barriers to lateral transport of free charge carriers in the active region and preventing their nonradiative surface recombination. For the first time, temperature stability of InGaN/GaN microring lasers characteristics are studied and lasing up to 100 degrees Celsius is demonstrated with the wavelength shift less than 1 nm. At room temperature, the threshold pump power is as low as 220 kW/cm<inline-formula> <tex-math>${}^{mathbf {2}}$ </tex-math></inline-formula>. The obtained results significantly expand the potential areas of application of III-N microlasers.","PeriodicalId":13065,"journal":{"name":"IEEE Photonics Technology Letters","volume":"38 4","pages":"243-246"},"PeriodicalIF":2.5,"publicationDate":"2025-11-03","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145500493","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 : 2025-11-03DOI: 10.1109/LPT.2025.3627981
Kan Tian;Wei-Zhe Wang;Yu-Chao Zhou;Jun-Bo Mao;Yu-Fen Sun;Mao-Xing Xiang;Tao Pu;Xiao-Shuai Guo;Chang-Tao He;Wen-Long Li;Hou-Kun Liang;Yong-Hua Shi
We present a temperature-tuning optical parametric amplifier (OPA) based on a BaGa4S7 (BGS) crystal, which enables alignment-free spectral tuning across the mid-infrared (MIR) wavelength range. Utilizing the temperature-dependent birefringence of BGS, continuous wavelength tuning is realized without mechanical adjustment of the crystal phase-matching (PM) angle. With fixed PM angles of $theta = 4.1^{circ }$ and 11.1°, the system achieves broadband spectral tunability from 5.8–$7.35~mu $ m and 7–$10.3mu $ m, respectively, over a crystal temperature range of 20–160°C, covering molecular fingerprint regions. The alignment-free tuning mechanism ensures excellent beam-pointing stability, thereby addressing a key limitation of conventional angle-tuned OPAs. These results demonstrate that BGS serves as a flexible platform for temperature-controlled MIR light sources, offering a scalable solution for achieving spectral agility in ultrafast laser systems. This approach holds promise for applications such as molecular spectroscopy, where it eliminates the need for mechanical complexity and alignment procedures.
{"title":"Broadband Tunable Optical Parametric Amplifier Based on Temperature Variation of BaGa4S7 Crystal","authors":"Kan Tian;Wei-Zhe Wang;Yu-Chao Zhou;Jun-Bo Mao;Yu-Fen Sun;Mao-Xing Xiang;Tao Pu;Xiao-Shuai Guo;Chang-Tao He;Wen-Long Li;Hou-Kun Liang;Yong-Hua Shi","doi":"10.1109/LPT.2025.3627981","DOIUrl":"https://doi.org/10.1109/LPT.2025.3627981","url":null,"abstract":"We present a temperature-tuning optical parametric amplifier (OPA) based on a BaGa4S7 (BGS) crystal, which enables alignment-free spectral tuning across the mid-infrared (MIR) wavelength range. Utilizing the temperature-dependent birefringence of BGS, continuous wavelength tuning is realized without mechanical adjustment of the crystal phase-matching (PM) angle. With fixed PM angles of <inline-formula> <tex-math>$theta = 4.1^{circ }$ </tex-math></inline-formula> and 11.1°, the system achieves broadband spectral tunability from 5.8–<inline-formula> <tex-math>$7.35~mu $ </tex-math></inline-formula>m and 7–<inline-formula> <tex-math>$10.3mu $ </tex-math></inline-formula>m, respectively, over a crystal temperature range of 20–160°C, covering molecular fingerprint regions. The alignment-free tuning mechanism ensures excellent beam-pointing stability, thereby addressing a key limitation of conventional angle-tuned OPAs. These results demonstrate that BGS serves as a flexible platform for temperature-controlled MIR light sources, offering a scalable solution for achieving spectral agility in ultrafast laser systems. This approach holds promise for applications such as molecular spectroscopy, where it eliminates the need for mechanical complexity and alignment procedures.","PeriodicalId":13065,"journal":{"name":"IEEE Photonics Technology Letters","volume":"38 3","pages":"203-206"},"PeriodicalIF":2.5,"publicationDate":"2025-11-03","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145500492","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}
In this letter, we report the fabrication and characterization of a metal–semiconductor–metal (MSM) deep-ultraviolet (DUV) photodetector based on $alpha $ -Ga2O3 thin films grown by mist chemical vapor deposition (mist-CVD). The $alpha $ -Ga2O3 films exhibit excellent crystallinity and surface uniformity, enabling the realization of high-performance DUV photodetectors. The fabricated device achieves an ultra-high responsivity exceeding 1000 A/W at 210 nm, an ultra-low dark current of 0.12 pA at 5 V, and a high UV-to-visible rejection ratio of $sim 10^{5}$ . In addition, a temporal response with a decay time of millisecond scale is observed. These results demonstrate the viability of mist-CVD-grown $alpha $ -Ga2O3 for scalable and cost-effective fabrication of next-generation DUV optoelectronic devices.
{"title":"High Performance α-Ga2O3 Deep Ultraviolet Photodetector Grown by Mist-CVD","authors":"Haoxuan Peng;Suhao Yao;Yingxu Wang;Maolin Zhang;Weihua Tang;Yufeng Guo","doi":"10.1109/LPT.2025.3627605","DOIUrl":"https://doi.org/10.1109/LPT.2025.3627605","url":null,"abstract":"In this letter, we report the fabrication and characterization of a metal–semiconductor–metal (MSM) deep-ultraviolet (DUV) photodetector based on <inline-formula> <tex-math>$alpha $ </tex-math></inline-formula>-Ga2O3 thin films grown by mist chemical vapor deposition (mist-CVD). The <inline-formula> <tex-math>$alpha $ </tex-math></inline-formula>-Ga2O3 films exhibit excellent crystallinity and surface uniformity, enabling the realization of high-performance DUV photodetectors. The fabricated device achieves an ultra-high responsivity exceeding 1000 A/W at 210 nm, an ultra-low dark current of 0.12 pA at 5 V, and a high UV-to-visible rejection ratio of <inline-formula> <tex-math>$sim 10^{5}$ </tex-math></inline-formula>. In addition, a temporal response with a decay time of millisecond scale is observed. These results demonstrate the viability of mist-CVD-grown <inline-formula> <tex-math>$alpha $ </tex-math></inline-formula>-Ga2O3 for scalable and cost-effective fabrication of next-generation DUV optoelectronic devices.","PeriodicalId":13065,"journal":{"name":"IEEE Photonics Technology Letters","volume":"38 4","pages":"219-222"},"PeriodicalIF":2.5,"publicationDate":"2025-10-31","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145500496","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 : 2025-10-30DOI: 10.1109/LPT.2025.3626792
Chun-Yuan Fan;Chi-Jung Huang;Chi-Ming Lai
This Letter presents the design and properties of a polarization-selective metasurface tailored for smart buildings and visible light communication. The proposed design features unit cells with a perforated hexagonal structure, enabling resonance modes for specific polarizations. The results demonstrate high transmission around 28 GHz for a particular linear polarization, with a transmittance of approximately 70%, while reflecting the orthogonal polarization with a transmittance below 5%. Moreover, the metasurface is compatible with wide-angle 5G signals and achieves 85% high transmittance in the visible light spectrum, regardless of polarization. Unlike prior multilayer approaches, our structure is realized by a single patterned copper layer on a dielectric substrate, enabling scalable fabrication and practical integration. This polarization-selective metasurface can seamlessly integrate into the smart glass, providing natural light transmission while filtering communication signals for enhanced privacy and functionality.
{"title":"Polarization-Selective Metasurface for 5G Band Communication With High Visible Light Transmission","authors":"Chun-Yuan Fan;Chi-Jung Huang;Chi-Ming Lai","doi":"10.1109/LPT.2025.3626792","DOIUrl":"https://doi.org/10.1109/LPT.2025.3626792","url":null,"abstract":"This Letter presents the design and properties of a polarization-selective metasurface tailored for smart buildings and visible light communication. The proposed design features unit cells with a perforated hexagonal structure, enabling resonance modes for specific polarizations. The results demonstrate high transmission around 28 GHz for a particular linear polarization, with a transmittance of approximately 70%, while reflecting the orthogonal polarization with a transmittance below 5%. Moreover, the metasurface is compatible with wide-angle 5G signals and achieves 85% high transmittance in the visible light spectrum, regardless of polarization. Unlike prior multilayer approaches, our structure is realized by a single patterned copper layer on a dielectric substrate, enabling scalable fabrication and practical integration. This polarization-selective metasurface can seamlessly integrate into the smart glass, providing natural light transmission while filtering communication signals for enhanced privacy and functionality.","PeriodicalId":13065,"journal":{"name":"IEEE Photonics Technology Letters","volume":"38 3","pages":"211-214"},"PeriodicalIF":2.5,"publicationDate":"2025-10-30","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://ieeexplore.ieee.org/stamp/stamp.jsp?tp=&arnumber=11220957","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145500523","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
An all-fiber acousto-optic spectrometer is proposed and experimentally demonstrated based on acoustically-induced fiber gratings (AIFGs) in cladding-etched single-mode fiber. The spectrometer has a wavelength measurement range of 100 nm, a wavelength resolution of ~15 nm, a maximal wavelength scanning speed of ~73500 nm/s, and a limit spectrum measurement time of 1 ms/frame, which is utilized in experimental observation of the transient spectrum of fast tunable lasers. The spectrometer has the potential to be developed as a miniaturized, low-cost and fast spectral measurement device for applications in astronomical detection, gas detection and photoelectric device characterization.
{"title":"All-Fiber Acousto-Optic Spectrometer Based on Acoustically Induced Fiber Gratings","authors":"Ligang Huang;Hailin Zhou;Shunli Liu;Yanxiang Zhao;Lei Gao;Yujia Li;Guiyao Zhou;Tao Zhu","doi":"10.1109/LPT.2025.3626725","DOIUrl":"https://doi.org/10.1109/LPT.2025.3626725","url":null,"abstract":"An all-fiber acousto-optic spectrometer is proposed and experimentally demonstrated based on acoustically-induced fiber gratings (AIFGs) in cladding-etched single-mode fiber. The spectrometer has a wavelength measurement range of 100 nm, a wavelength resolution of ~15 nm, a maximal wavelength scanning speed of ~73500 nm/s, and a limit spectrum measurement time of 1 ms/frame, which is utilized in experimental observation of the transient spectrum of fast tunable lasers. The spectrometer has the potential to be developed as a miniaturized, low-cost and fast spectral measurement device for applications in astronomical detection, gas detection and photoelectric device characterization.","PeriodicalId":13065,"journal":{"name":"IEEE Photonics Technology Letters","volume":"38 3","pages":"188-191"},"PeriodicalIF":2.5,"publicationDate":"2025-10-30","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145500459","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 : 2025-10-30DOI: 10.1109/LPT.2025.3626726
Aaron Wissing;James Dalton;Evan Chansky;Zachery Bloom;Xinhong Du;Larry A. Coldren;Adel A. M. Saleh;James F. Buckwalter;Clint L. Schow
We demonstrate a monolithically integrated O-band silicon photonics five-segment Mach-Zehnder modulator with a distributed driver in a 45-nm CMOS process, packaged with wirebonds on a PCB. Each segment includes a cascode driver and 0.7 mm traveling-wave electrode with a termination. Open eyes and BERs below the KP-4 and KR-4 FEC threshold are measured up to 40 Gbaud with 3.09 pJ/bit energy efficiency, without feedforward equalization (FFE). Open eyes and BER below the KP-4 FEC threshold are also measured at 50 Gbaud with 2.47 pJ/bit energy efficiency using an analog 5-tap finite impulse response (FIR) equalizer. The design approach enabled a low power consumption of 116.5 mW.
{"title":"A Monolithically Integrated Five-Segment Mach–Zehnder Modulator With Distributed Driver in 45-nm CMOS","authors":"Aaron Wissing;James Dalton;Evan Chansky;Zachery Bloom;Xinhong Du;Larry A. Coldren;Adel A. M. Saleh;James F. Buckwalter;Clint L. Schow","doi":"10.1109/LPT.2025.3626726","DOIUrl":"https://doi.org/10.1109/LPT.2025.3626726","url":null,"abstract":"We demonstrate a monolithically integrated O-band silicon photonics five-segment Mach-Zehnder modulator with a distributed driver in a 45-nm CMOS process, packaged with wirebonds on a PCB. Each segment includes a cascode driver and 0.7 mm traveling-wave electrode with a termination. Open eyes and BERs below the KP-4 and KR-4 FEC threshold are measured up to 40 Gbaud with 3.09 pJ/bit energy efficiency, without feedforward equalization (FFE). Open eyes and BER below the KP-4 FEC threshold are also measured at 50 Gbaud with 2.47 pJ/bit energy efficiency using an analog 5-tap finite impulse response (FIR) equalizer. The design approach enabled a low power consumption of 116.5 mW.","PeriodicalId":13065,"journal":{"name":"IEEE Photonics Technology Letters","volume":"38 4","pages":"251-254"},"PeriodicalIF":2.5,"publicationDate":"2025-10-30","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145560812","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 : 2025-10-30DOI: 10.1109/LPT.2025.3627444
Yicheng Zhu;Wenjuan Wang;Min Zhou;Huidan Qu;Zhi Zhen;Pingping Chen;Wei Lu
Metalenses, which can freely manipulate light fields, are regarded as highly promising optical components for enhancing the performance of photodetectors. In this letter, a novel InGaAs/InP single-photon avalanche diode (SPAD) with small active diameter and backside InP metalens is presented. The active area, with a diameter of $8mu $ m, is complemented by a $100mu $ m $times 100mu $ m metalens that focuses incident photons into the photosensitive region. The focused beam size of the metalens is approximately $1.3mu $ m (full width at half-maximum) at the target focal plane. The novel SPAD with backside metalens achieves a maximum photon detection efficiency (PDE) of 15.9% at a wavelength of 1550 nm. Comparative experiments indicate that the integration of the metalens provides a 37% relative-increase in maximum PDE while maintaining a compact size. This work provides a new way for the realization of small-pixel, high-PDE InGaAs/InP SPAD arrays and supports the development of miniaturized, multi-dimensional photon detectors.
{"title":"Monolithic Integration of InP Metalens With InGaAs/InP Single Photon Avalanche Diode","authors":"Yicheng Zhu;Wenjuan Wang;Min Zhou;Huidan Qu;Zhi Zhen;Pingping Chen;Wei Lu","doi":"10.1109/LPT.2025.3627444","DOIUrl":"https://doi.org/10.1109/LPT.2025.3627444","url":null,"abstract":"Metalenses, which can freely manipulate light fields, are regarded as highly promising optical components for enhancing the performance of photodetectors. In this letter, a novel InGaAs/InP single-photon avalanche diode (SPAD) with small active diameter and backside InP metalens is presented. The active area, with a diameter of <inline-formula> <tex-math>$8mu $ </tex-math></inline-formula> m, is complemented by a <inline-formula> <tex-math>$100mu $ </tex-math></inline-formula>m <inline-formula> <tex-math>$times 100mu $ </tex-math></inline-formula>m metalens that focuses incident photons into the photosensitive region. The focused beam size of the metalens is approximately <inline-formula> <tex-math>$1.3mu $ </tex-math></inline-formula>m (full width at half-maximum) at the target focal plane. The novel SPAD with backside metalens achieves a maximum photon detection efficiency (PDE) of 15.9% at a wavelength of 1550 nm. Comparative experiments indicate that the integration of the metalens provides a 37% relative-increase in maximum PDE while maintaining a compact size. This work provides a new way for the realization of small-pixel, high-PDE InGaAs/InP SPAD arrays and supports the development of miniaturized, multi-dimensional photon detectors.","PeriodicalId":13065,"journal":{"name":"IEEE Photonics Technology Letters","volume":"38 4","pages":"271-274"},"PeriodicalIF":2.5,"publicationDate":"2025-10-30","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145612217","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 : 2025-10-30DOI: 10.1109/LPT.2025.3626739
Yongli Liu;Pingan Liu;Zhaohui Zhang;Liguo Zhu
We report a high-spatial-resolution distributed temperature sensing system using an asynchronous mode-locked fiber laser. It employs two picosecond pulse trains with a 6,100 Hz repetition rate difference. One is amplified as pump light (~46 ps) to excite Raman scattering, while the other serves as an asynchronous probe. A low-speed data acquisition card with short aperture time and a broadband avalanche photodetector are used to achieve millimeter-level resolution. Experiments under high-temperature gradients demonstrate 9.2 mm spatial resolution over ~2 meters of fiber. The asynchronous sampling enables full waveform acquisition within $163mu $ s, greatly improving efficiency. This is the first application of a bidirectional ultrafast laser in distributed sensing, offering strong potential for OTDR-based systems.
{"title":"Millimeter-Scale Spatial Resolution Raman Sensing System Enabled by Bidirectional Fiber Laser","authors":"Yongli Liu;Pingan Liu;Zhaohui Zhang;Liguo Zhu","doi":"10.1109/LPT.2025.3626739","DOIUrl":"https://doi.org/10.1109/LPT.2025.3626739","url":null,"abstract":"We report a high-spatial-resolution distributed temperature sensing system using an asynchronous mode-locked fiber laser. It employs two picosecond pulse trains with a 6,100 Hz repetition rate difference. One is amplified as pump light (~46 ps) to excite Raman scattering, while the other serves as an asynchronous probe. A low-speed data acquisition card with short aperture time and a broadband avalanche photodetector are used to achieve millimeter-level resolution. Experiments under high-temperature gradients demonstrate 9.2 mm spatial resolution over ~2 meters of fiber. The asynchronous sampling enables full waveform acquisition within <inline-formula> <tex-math>$163mu $ </tex-math></inline-formula> s, greatly improving efficiency. This is the first application of a bidirectional ultrafast laser in distributed sensing, offering strong potential for OTDR-based systems.","PeriodicalId":13065,"journal":{"name":"IEEE Photonics Technology Letters","volume":"38 3","pages":"207-210"},"PeriodicalIF":2.5,"publicationDate":"2025-10-30","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145500481","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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