IEEE Photonics Journal最新文献

{"title":"High-Performance AlGaN-Based UV-A Laser Diodes With Polarization-Modulated Superlattice Hole Injection and a Graded Electron-Blocking Layer","authors":"Xinyu Yang;Qilin Tan;Lingfang Yang;Deyi Fu;Na Gao;Shuping Li;Junyong Kang;Rong Zhang","doi":"10.1109/JPHOT.2026.3712465","DOIUrl":"https://doi.org/10.1109/JPHOT.2026.3712465","url":null,"abstract":"Carrier imbalance—characterized by an electron-rich active region caused by limited hole injection—has long been a major challenge for AlGaN-based UV-A laser diodes, severely degrading their optoelectronic performance. In this work, we investigate AlGaN-based UV-A laser diodes emitting at approximately 358 nm and propose a hybrid design that combines a thin-well p-AlGaN/GaN superlattice hole-injection layer with a compositionally graded AlGaN electron-blocking layer (EBL) to simultaneously enhance hole injection and suppress electron leakage, thereby restoring electron-hole injection balance and improving carrier transport. Numerical simulations demonstrate that the superlattice markedly reduces the polarization-induced electric field near the EBL, alleviating interfacial carrier accumulation and boosting the local hole concentration in the p-type region by more than two orders of magnitude. Moreover, the graded EBL provides improved barrier modulation, suppressing electron leakage while facilitating hole injection, thereby enhancing the radiative recombination rate. Compared with the conventional structure with fixed compositions, the output optical power increases by 240%, and the wall-plug efficiency increases by 386.2%. These results suggest a promising strategy for achieving highly efficient hole injection in AlGaN-based UV-A laser diodes.","PeriodicalId":13204,"journal":{"name":"IEEE Photonics Journal","volume":"18 4","pages":"1501906-1501906"},"PeriodicalIF":2.6,"publicationDate":"2026-08-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://ieeexplore.ieee.org/stamp/stamp.jsp?tp=&arnumber=11604130","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"148626084","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Design Method of Large-Field-of-View Baffle for Space Target Detection","authors":"Shuaiwei Mu;Yuanhao Xie;Haolin Qi;Jiajian Guo;Lei Yan;Xin Zhang;Hongbo Wu;Shuanglong Tan","doi":"10.1109/JPHOT.2026.3697745","DOIUrl":"https://doi.org/10.1109/JPHOT.2026.3697745","url":null,"abstract":"Stray light suppression is critical for ensuring the detection capability of wide-area space-target detection optical systems, and baffle design serves as the primary method for achieving this suppression. To effectively suppress stray light in wide-area detection optical systems for space targets, this paper proposes a design methodology for wide field of view (61°) baffles. Initially, we construct a detection range inversion model and a stray light suppression capability evaluation model for space target detection, deriving and calculating the point source transmittance (PST) value required to achieve the system’s detection capability (6th magnitude star). Subsequently, we derive and summarize the calculation and design methodologies for baffles of different configurations, proposing a two-stage baffle design approach. Finally, we perform structural design and stray light suppression capability simulation verification for this two-stage baffle. The results indicate that the two-stage wide FOV baffle designed using this methodology can effectively suppress large-angle stray light, meeting the engineering application requirements of practical wide-area space target detection.","PeriodicalId":13204,"journal":{"name":"IEEE Photonics Journal","volume":"18 4","pages":"7900614-7900614"},"PeriodicalIF":2.6,"publicationDate":"2026-08-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://ieeexplore.ieee.org/stamp/stamp.jsp?tp=&arnumber=11536875","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"148626135","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Effect of Mode Competition in Elliptical Aperture VCSELs Under PAM4 Modulation","authors":"Cristina Rimoldi;Marco Novarese;Leonardo Minelli;Mariacristina Casasco;Tong Shao;Sebastian Romero García;Roberto Gaudino;Valter Ferrero;Mariangela Gioannini","doi":"10.1109/JPHOT.2026.3710293","DOIUrl":"https://doi.org/10.1109/JPHOT.2026.3710293","url":null,"abstract":"We analyze the noise performance of multimode VCSELs under PAM4 modulation. For the first time, we develop a method that allows us to isolate the contribution of the modulation current from the overall Relative Intensity Noise (RIN) spectrum. As a result, we show that peaks in the RIN persist under modulation and can impact both noise performances and the Transmitter and Dispersion Eye Closure Quaternary (TDECQ) metrics.","PeriodicalId":13204,"journal":{"name":"IEEE Photonics Journal","volume":"18 4","pages":"1502008-1502008"},"PeriodicalIF":2.6,"publicationDate":"2026-08-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://ieeexplore.ieee.org/stamp/stamp.jsp?tp=&arnumber=11595508","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"148626462","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Performance Analysis of VLC Systems Over Random Channels With Signal-Dependent Shot Noise and Relative Intensity Noise","authors":"Sara H. ElFar;Salama Ikki;Abdel Razik Sebak","doi":"10.1109/JPHOT.2026.3714407","DOIUrl":"https://doi.org/10.1109/JPHOT.2026.3714407","url":null,"abstract":"Signal-dependent shot noise (SDSN) and relative intensity noise (RIN) are important practical impairments in visible light communication (VLC) systems because their noise variances depend on the received optical signal level. This paper develops a comprehensive analytical framework for evaluating the reliability and achievable-rate performance of a bounded line-of-sight VLC system with a randomly located receiver under thermal noise, SDSN, and RIN. A closed-form piecewise outage probability expression is derived by accounting for the bounded channel-gain support, and the corresponding finite-SNR local outage slope is obtained to characterize the outage-decay behavior in the partial-outage region. The analysis reveals that SDSN changes the power-scaling behavior of the system, whereas RIN imposes an SNR ceiling that can fundamentally limit reliability improvement at high transmit power. In addition, the ergodic Shannon-type rate is characterized through its exact channel-gain integral and a rigorously derived closed-form analytical upper bound. High-power asymptotic expressions are obtained separately for the exact rate and the analytical upper bound, revealing distinct behaviors under RIN-dominated, SDSN-dominated, and thermal-noise-limited conditions. In particular, RIN produces a finite achievable-rate ceiling, while SDSN reduces the rate-growth behavior compared with the thermal-noise-only regime. Numerical integration and Monte Carlo simulations confirm the accuracy of the derived outage, local-slope, rate-bound, and asymptotic expressions. The results demonstrate that neglecting SDSN and RIN can lead to overly optimistic reliability and achievable-rate predictions in practical VLC systems.","PeriodicalId":13204,"journal":{"name":"IEEE Photonics Journal","volume":"18 4","pages":"7301615-7301615"},"PeriodicalIF":2.6,"publicationDate":"2026-08-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://ieeexplore.ieee.org/stamp/stamp.jsp?tp=&arnumber=11613142","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"148626789","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Photonics Breakthroughs 2025: Mask-Based Integrated Miniscope for Large-scale Volumetric Imaging","authors":"Feng Tian;Weijian Yang","doi":"10.1109/JPHOT.2026.3706745","DOIUrl":"https://doi.org/10.1109/JPHOT.2026.3706745","url":null,"abstract":"Mask-based integrated microscopy represents a powerful computational imaging paradigm, enabling 3D imaging over a large field of view within a thin device footprint. This architecture leverages a thin optical mask to encode object information onto a camera sensor placed in close proximity. A major challenge in this field is to maintain high reconstruction quality amid low signal-to-background ratios, while simultaneously reducing computational requirements to allow for larger reconstruction volumes. Here, we describe a significant breakthrough in this area: DeepInMiniscope, a system featuring a highly scalable reconstruction algorithm for high-quality imaging over large 3D volumes. We detail the joint development of the hardware and reconstruction algorithms that enable this high-quality, efficient, and robust imaging framework, and present its capability to record neural activity in the mouse brain with near-cellular resolution. DeepInMiniscope represents a key step towards large-scale, 3D functional recording in freely-behaving animals.","PeriodicalId":13204,"journal":{"name":"IEEE Photonics Journal","volume":"18 4","pages":"3900408-3900408"},"PeriodicalIF":2.6,"publicationDate":"2026-08-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://ieeexplore.ieee.org/stamp/stamp.jsp?tp=&arnumber=11575725","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"148626290","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Optimization of Single Photon Avalanche Diode Design Using Surrogate-Reinforcement Learning","authors":"Kazi Mohammad Mamun;Nezih Pala;Mst Shamim Ara Shawkat","doi":"10.1109/JPHOT.2026.3710044","DOIUrl":"https://doi.org/10.1109/JPHOT.2026.3710044","url":null,"abstract":"This paper presents the optimization of Single-Photon Avalanche Diode (SPAD) device design parameters using surrogate-assisted reinforcement learning (RL) framework. Both Sentaurus Technology Computer-Aided Design (TCAD) and MATLAB simulations are used to generate datasets that capture the relationship between SPAD geometry, doping concentrations, and avalanche triggering probability. Avalanche triggering probability significantly affects the key performance metric of SPAD devices, including photon detection probability (PDP), dark count rate (DCR), and breakdown voltage. Upon training, we evaluate four machine learning (ML) models using our dataset and choose Extreme Gradient Boosting (XGBoost) as high performing surrogate model that accurately predicts the avalanche triggering probability from SPAD design parameters. The trained surrogate is integrated into a RL environment, enabling multiple RL agents, including Proximal Policy Optimization (PPO), Advantage Actor–Critic (A2C), Soft Actor–Critic (SAC), and Temporal-Difference Model Predictive Control 2 (TD-MPC2) to efficiently explore and optimize the SPAD design space without repeated TCAD simulations. The proposed optimization framework successfully identifies multiple high performance SPAD configurations, achieving avalanche triggering probabilities above 0.55 with TCAD validation errors below 4%. Both single-stage and multi-stage learning strategies are investigated, demonstrating improved convergence and optimization stability through staged exploration and exploitation. In addition, dark count rate (DCR) performance, effective noise of SPAD devices, is evaluated confirming that the optimized designs maintain favorable noise performance. Additionally, the proposed surrogate assisted RL-based SPAD optimization substantially reduces the computational cost compared to conventional TCAD-driven optimization. The results demonstrate that surrogate-assisted RL framework provides an efficient and viable alternative to conventional TCAD-driven SPAD design optimization.","PeriodicalId":13204,"journal":{"name":"IEEE Photonics Journal","volume":"18 4","pages":"8500416-8500416"},"PeriodicalIF":2.6,"publicationDate":"2026-08-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://ieeexplore.ieee.org/stamp/stamp.jsp?tp=&arnumber=11594409","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"148746894","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Photonics Breakthroughs 2025: Advances in Doppler Effects of Structured Light Fields","authors":"Zhenyu Wan;Ziyi Tang;Jian Wang","doi":"10.1109/JPHOT.2026.3712743","DOIUrl":"https://doi.org/10.1109/JPHOT.2026.3712743","url":null,"abstract":"The Doppler effect is a fundamental and widely observed physical phenomenon. In recent years, the conventional Doppler effect has evolved into the rotational and vectorial forms with the study of structured light. Particularly, for beams with angularly-distributed phase, the skew Poynting vector would give rise to Doppler shifts when interacting with transverse motions, namely the rotational Doppler effect (RDE). Here, we highlight recent breakthroughs in both principles and applications of Doppler effects associated with structured fields. One such breakthrough is the demonstration of the structure-shearing Doppler effect (SDE). Recent studies suggest that the spatial structures of light beams would provide a modification of the group and phase velocities of optical fields, and then an open question remains how the spatial confinement on optical fields affects the Doppler shifts of structured beams. We found that the transverse structure of optical fields naturally causes an extra red shift on the original Doppler shift. Another breakthrough concerns the miniaturization of optical metrology and sensing instrument. The first all-fiber rotational Doppler velocimetry (AF-RDV) is designed and fabricated with mode-sculpted fiber-optic elements, enabling compact, cost-effective, and reference-free angular velocity sensing. By leveraging mode-selective coupling, the system reveals the mode-change-dependent nature of the RDE and shows great promise for biomedical and industrial applications.","PeriodicalId":13204,"journal":{"name":"IEEE Photonics Journal","volume":"18 4","pages":"3100307-3100307"},"PeriodicalIF":2.6,"publicationDate":"2026-08-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://ieeexplore.ieee.org/stamp/stamp.jsp?tp=&arnumber=11606250","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"148626275","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Low-Complexity Self-Coherent Optical Transmission Scheme Based on Dual-Fiber Differential Detection","authors":"Hui Yang;Lu Zhang;Xiaojun Xie;Anlin Yi;Lin Jiang;Xihua Zou;Lianshan Yan;Wei Pan","doi":"10.1109/JPHOT.2026.3710360","DOIUrl":"https://doi.org/10.1109/JPHOT.2026.3710360","url":null,"abstract":"To address the demand for low cost and low power consumption in short- to medium-reach optical interconnects, this paper proposes a self-coherent optical transmission scheme based on dual-fiber differential detection. At the transmitter, a single-polarization in-phase/quadrature (IQ) modulator is employed to generate the modulated optical signal, which is subsequently split into two branches. One branch is coupled with an unmodulated carrier from the same optical source prior to transmission, while the other is transmitted independently as a pure signal branch. At the receiver, a balanced photodetector (BPD) is utilized for differential detection. This extracts the carrier-signal beat term while physically canceling signal-signal beat interference (SSBI), signal-amplified spontaneous emission (ASE) beat noise, and ASE-ASE beat noise. Compared with single-photodetector reception schemes, such as Kramers-Kronig (KK) receivers, the proposed scheme effectively suppresses the aforementioned common-mode noises, eliminates the requirement for a high carrier-to-signal power ratio (CSPR), and circumvents the need for high-complexity optical field recovery algorithms. Furthermore, by co-transmitting the carrier and the signal over the same fiber, the proposed scheme avoids the inherent polarization fading issue prevalent in conventional dual-fiber systems. Numerical simulations employing a 32 Gbaud 16-QAM signal demonstrate that, at the 7% hard-decision forward error correction (HD-FEC) threshold, the proposed scheme achieves a 7.1 dB optical signal-to-noise ratio (OSNR) gain over the KK receiver. Additionally, the system exhibits high robustness against laser linewidth broadening and dual-fiber length mismatch, providing a viable technical pathway for low-complexity optical transceivers.","PeriodicalId":13204,"journal":{"name":"IEEE Photonics Journal","volume":"18 4","pages":"7900707-7900707"},"PeriodicalIF":2.6,"publicationDate":"2026-08-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://ieeexplore.ieee.org/stamp/stamp.jsp?tp=&arnumber=11595529","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"148626736","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"A Reconfigurable Dual-Mode Front-End Circuit With Shared Active-Quench Loop and Bias-Tunable Dead Time for Single-Photon Avalanche Diodes","authors":"Zikun Cai;Xiaotong Zhang;Yudi Huang;Zhangcheng Huang;Jianlu Wang","doi":"10.1109/JPHOT.2026.3715967","DOIUrl":"https://doi.org/10.1109/JPHOT.2026.3715967","url":null,"abstract":"This paper presents a reconfigurable front-end circuit for Single-Photon Avalanche Diodes (SPADs), capable of seamless switching between synchronous time-gated detection and asynchronous free-running photon counting. To minimize silicon area and reduce parasitic capacitance, the proposed architecture employs a shared high-speed active-quenching circuit for both operation modes. In the free-running mode, a bias-controlled current-starved delay path is implemented to provide a programmable dead time, enabling an adaptive trade-off between afterpulsing suppression and the maximum photon count rate. Experimental results demonstrate that the circuit achieves a timing histogram Full Width at Half Maximum (FWHM) of 70 ps in time-gated mode. Furthermore, the free-running mode exhibits a continuously tunable dead time ranging from 2.73 ns to over 100 μs. These results demonstrate the suitability of the proposed circuit for scalable SPAD array readout systems requiring high temporal resolution and adaptive operating modes.","PeriodicalId":13204,"journal":{"name":"IEEE Photonics Journal","volume":"18 4","pages":"7800410-7800410"},"PeriodicalIF":2.6,"publicationDate":"2026-08-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://ieeexplore.ieee.org/stamp/stamp.jsp?tp=&arnumber=11617300","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"148747062","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Real-Time Distributed Fiber Sensing Using FPGA-Accelerated Sliding-Window Correlation: From IM-DD to Coherent Detection","authors":"Botao Yang;Tao Zeng;Te Ke;Yimei Pan;Chen Wang;Ziye Zhong;Ziqing Liu;Ming Luo;Xi Xiao;Hanbing Li","doi":"10.1109/JPHOT.2026.3713186","DOIUrl":"https://doi.org/10.1109/JPHOT.2026.3713186","url":null,"abstract":"This paper presents and experimentally demonstrates an FPGA-accelerated correlation optical time-domain reflectometry (C-OTDR) architecture for distributed fiber sensing, spanning both intensity-modulation/direct-detection (IM-DD) and coherent dual-polarization quadrature phase-shift keying (DP-QPSK) implementations. In the IM-DD configuration, a hardware-optimized “overview-then-zoom-in” strategy enables high signal-to-noise ratio (SNR) inspection over ultra-long links, achieving a 2-cm spatial resolution at 95 km and delivering an ≈20 dB SNR enhancement via deep accumulation within targeted segments. Extending this framework to the coherent domain, we implement a real-time sliding-window correlation engine directly on the FPGA, eliminating offline post-processing. Over a 40-km standard single-mode fiber span, the coherent system achieves a 3.53-cm point spacing, resolves four consecutive connectors spaced 100 cm apart near the far end, and simultaneously extracts a 20-km attenuation profile alongside a highly repeatable Rayleigh backscatter pattern that serves as a stable “fiber fingerprint.” This work establishes a practical, hardware-efficient pathway toward real-time coherent distributed sensing, offering native compatibility with modern optical communication networks.","PeriodicalId":13204,"journal":{"name":"IEEE Photonics Journal","volume":"18 4","pages":"6802008-6802008"},"PeriodicalIF":2.6,"publicationDate":"2026-08-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://ieeexplore.ieee.org/stamp/stamp.jsp?tp=&arnumber=11609346","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"148747853","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}