{"title":"Polarization-Dependent Loss Mitigation via Orthogonal Design Precoding and Interference Cancellation","authors":"Mohannad Shehadeh;Frank R. Kschischang","doi":"10.1109/LPT.2025.3555919","DOIUrl":"https://doi.org/10.1109/LPT.2025.3555919","url":null,"abstract":"Recent work by Shehadeh and Kschischang provides a simple capacity-achieving scheme for channels with polarization-dependent loss (PDL) under common modeling assumptions via a careful choice of orthogonal-design-based precoding and interference cancellation. This letter extends that work with a simulation-based demonstration showing that this scheme remains highly effective at mitigating PDL in the highly practical setting of 16-QAM with Chase-decoded extended Hamming inner codes rather than the near-capacity inner codes considered in the original work. An alternative near-optimal variation of this scheme is also provided requiring only one inner code rather than two and suffering no penalty in the absence of PDL, making it much more practical.","PeriodicalId":13065,"journal":{"name":"IEEE Photonics Technology Letters","volume":"37 8","pages":"477-480"},"PeriodicalIF":2.3,"publicationDate":"2025-03-28","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143800999","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}
Sicheng Guo;Tao Cheng;Kangjian Yang;Lingxi Kong;Shuai Wang;Ping Yang
{"title":"Beam Jitter Suppression Method for Large-Aperture Tip-Tilt Mirrors With Non-Negligible Resonance","authors":"Sicheng Guo;Tao Cheng;Kangjian Yang;Lingxi Kong;Shuai Wang;Ping Yang","doi":"10.1109/LPT.2025.3554761","DOIUrl":"https://doi.org/10.1109/LPT.2025.3554761","url":null,"abstract":"Effective control of large-aperture tip-tilt mirrors (TTMs) has been a pressing concern in beam stabilization due to the influence of their internal mechanical resonance. To the best of our knowledge, this Letter reports a new high-efficiency actor-critic (HEAC) scheme to effectively eliminate the impact of mechanical resonance on jitter suppression stabilization and performance. Moreover, HEAC features rapid deployment and training that rely solely on online noisy measurements through the establishment of a specific tracking control problem, the decoupling of the unknown system parameters, and the design of a quadratic homogeneous polynomial basis function network. The experimental results demonstrate that the HEAC has successfully achieved stable and efficient suppression of jitter near the resonance peak or close to the Nyquist frequency for a <inline-formula> <tex-math>$Phi ~405$ </tex-math></inline-formula>mm aperture TTM.","PeriodicalId":13065,"journal":{"name":"IEEE Photonics Technology Letters","volume":"37 9","pages":"536-539"},"PeriodicalIF":2.3,"publicationDate":"2025-03-26","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://ieeexplore.ieee.org/stamp/stamp.jsp?tp=&arnumber=10942387","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143845499","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}
{"title":"Low-Loss and Robust Arc-Discharge Fusion-Splicing Between Anti-Resonant Hollow-Core Fibers","authors":"Junjie Zeng;Cong Zhang;Yue Wang;Peng Li;Lei Zhang;Jie Luo;Lipeng Feng;Di Lin;Songnian Fu;Yuwen Qin","doi":"10.1109/LPT.2025.3554394","DOIUrl":"https://doi.org/10.1109/LPT.2025.3554394","url":null,"abstract":"Fusion splicing between anti-resonant hollow-core fibers (AR-HCFs) is the key enabler that opens practical applications of those fibers in low-latency and low-loss fiber optical communication. Here, the impact of angular misalignment and fiber overlap on the splicing loss, higher-order modes (HOMs) excitation, and polarization-dependent loss (PDL) of commonly-used AR-HCF with 5-nested tubes are comprehensively characterized. Simulation and experimental results reveal that the misalignment angle can introduce a maximum coupling loss of 0.12 dB while having almost no impact on HOMs excitation and PDL variation. Then, under the condition of perfect angular alignment, the parameter of fiber overlap during the splicing is optimized, and an average splicing loss of 0.05 dB over 10 times experiment is obtained, which is equivalent to the loss result of standard single mode fiber (SSMF) splicing. Spectral analysis shows that the normalized LP11 mode power has a slight increase from -31.62 dB to -28.33 dB, and the variation in PDL is less than 0.01 dB under the optimal fiber overlap of <inline-formula> <tex-math>$8~mu $ </tex-math></inline-formula>m, indicating that no structural deformation of AR-HCF thin tubes is introduced during the fusion splicing. Moreover, the mechanical robustness of the splicing is examined with a standard proof test returning a damage threshold of 250 gf @1 s. Our proposed fusion splicing technique can be extended to various AR-HCFs, providing the benefit of low-loss, robust, and repeatable interconnection between AR-HCFs.","PeriodicalId":13065,"journal":{"name":"IEEE Photonics Technology Letters","volume":"37 8","pages":"465-468"},"PeriodicalIF":2.3,"publicationDate":"2025-03-26","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143800998","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}
Jiehua Zhou;Yan Ding;Zhuo Yin;Xiaoyang Chen;Xiao Ma;Long Xiao;Cheng Lei
{"title":"A Programmable High-Precision Real-Time Optical Beamforming Network Based on Galois Field","authors":"Jiehua Zhou;Yan Ding;Zhuo Yin;Xiaoyang Chen;Xiao Ma;Long Xiao;Cheng Lei","doi":"10.1109/LPT.2025.3554773","DOIUrl":"https://doi.org/10.1109/LPT.2025.3554773","url":null,"abstract":"We propose a high-precision beam steering real-time control system that leverages optical true time delay (OTTD) based on serial <inline-formula> <tex-math>$2times 2$ </tex-math></inline-formula> optical switch differential delay pairs. The pre-designed OTTD system utilizes a three-layer structure including a host computer, main control module, and delay module, containing a set of coding rules for mapping delay to switch as well as reducing programming redundancy and a set of communication modules for on-chip communication and real-time control. To address the challenge of ultra-short fiber lengths, we introduce a method based on Galois field principles, exploiting phase periodicity. This approach allows us to determine fiber lengths without fabricating excessively short fibers, ensuring effective phase traversal and thus improving the system’s flexibility. The experimental results show that the system can switch states in real-time within 0.24 ms, with an angular deflection range of 1° between −60° and 60° in simulations, showing the potential of our method for flexible beamforming design.","PeriodicalId":13065,"journal":{"name":"IEEE Photonics Technology Letters","volume":"37 9","pages":"520-523"},"PeriodicalIF":2.3,"publicationDate":"2025-03-26","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143830439","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}
{"title":"Optical Funnel Effect of Fiber-End Conical Shell Light Field","authors":"Jiahao Du;Tingting Yuan;Xiaotong Zhang;Libo Yuan","doi":"10.1109/LPT.2025.3553910","DOIUrl":"https://doi.org/10.1109/LPT.2025.3553910","url":null,"abstract":"The manipulation and analysis of particles in fluid has always been a matter of concern. In the liquid microfluidic system, the quality of single cell flow directly affects the final analysis results. Due to its special structure, optical fiber has the advantages of simple structure and good compatibility and has become a cross-integration link in various research fields. In this letter, an integrated optical fiber structure for particle manipulation in fluid is proposed. The annular-core capillary fiber developed by the laboratory is adopted, which has the structure of cladding - annular core - air hole. The cone angle of 12° is polished at the exit end of the optical fiber. The laser transmitted by the annular core is reflected by the cone and forms a funnel-shaped cone shell light field at the end of the optical fiber, which is called ‘optical funnel’. When the particles are injected from the air hole and pass through the conical shell light field, the continuous directional control is formed due to the action of the light field force. The device has the characteristics of simple structure and high integration, which provides a solution for the miniaturization of instruments and equipment and is of great significance in engineering applications.","PeriodicalId":13065,"journal":{"name":"IEEE Photonics Technology Letters","volume":"37 8","pages":"489-492"},"PeriodicalIF":2.3,"publicationDate":"2025-03-25","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143817789","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}
Zhaozhao Li;Zhengkang Wang;Ruihuan Wu;Bo Li;Jiewei Chen;Weiyi Hong;Hongzhan Liu
{"title":"High-Speed Physical Random Bit Generation Based on Broadband Random Optoelectronic Oscillator","authors":"Zhaozhao Li;Zhengkang Wang;Ruihuan Wu;Bo Li;Jiewei Chen;Weiyi Hong;Hongzhan Liu","doi":"10.1109/LPT.2025.3554647","DOIUrl":"https://doi.org/10.1109/LPT.2025.3554647","url":null,"abstract":"A new approach for high-speed physical random bit generation (RBG) based on broadband random optoelectronic oscillator (OEO) is proposed and experimentally demonstrated. In this scheme, a broadband random OEO based on Rayleigh scattering (RS) is employed as the entropy source of RBG. Compared with other broadband random OEOs which require an additional pump source, the optical signal output from the laser in the proposed scheme can realize excited Brillouin scattering as well as acting as an optical carrier. Benefiting from the introduction of randomly distributed feedback by RS, which breaks the limitation of the fixed loop length of the conventional chaotic OEO, the signals generated by the proposed broadband random OEO have random characteristics. Meanwhile, the generated signals exhibit wide and flat frequency spectrum characteristics due to the avoidance of semiconductor chaotic laser relaxation oscillations. The experimental results show the proposed RBG technique can generate physical random bits with a rate of up to 500 Gb/s which can fully pass the NIST test.","PeriodicalId":13065,"journal":{"name":"IEEE Photonics Technology Letters","volume":"37 9","pages":"532-535"},"PeriodicalIF":2.3,"publicationDate":"2025-03-25","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143840093","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}
{"title":"Linearizing Optical Frequency Chirp of a Laser Diode for Accurate FMCW Optical Ranging","authors":"Meng Shan;Koichi Iiyama","doi":"10.1109/LPT.2025.3554238","DOIUrl":"https://doi.org/10.1109/LPT.2025.3554238","url":null,"abstract":"Optical frequency chirp of an external-cavity laser is linearized by optimizing the modulation waveform for long-range FMCW optical ranging system. The modulation signal of the laser is sampled with the interference signal of the auxiliary interferometer, and the sampled modulation signal is used as a new modulation signal. As a result, the optical frequency is linearly chirped. The linearization is realized at 50kHz modulation frequency and the measurement range of up to 66m optical fiber and up to 10m in free space. The linearity of the optical frequency chirp is evaluated by the ranging resolution and the ranging accuracy of the FMCW optical ranging system, and the ranging resolution is almost the theoretical limit, indicating that the optical frequency of the laser is highly linearly chirped.","PeriodicalId":13065,"journal":{"name":"IEEE Photonics Technology Letters","volume":"37 8","pages":"461-464"},"PeriodicalIF":2.3,"publicationDate":"2025-03-24","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143792938","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}
{"title":"Co-Existence of SiPh Sensing Link and Real World Traffic Over 100 m FSO Link for 6G Deployments","authors":"G. Syriopoulos;E. Kyriazi;T. Prousalidi;A. Ntanos;A. Stathis;P. Kourelias;P. Toumasis;H. Zervos;G. Giannoulis;G. Poulopoulos;H. Avramopoulos;D. Apostolopoulos","doi":"10.1109/LPT.2025.3554000","DOIUrl":"https://doi.org/10.1109/LPT.2025.3554000","url":null,"abstract":"We propose two configurations for the coexistence of sensing and communication signals, exploiting Free Space Optical (FSO) links to transmit commercial 6G traffic and remotely interrogate sensors distributed along distances of 100 m. The sensors are fabricated on a Silicon Photonics (SiPh) platform, to achieve miniaturization and highly compact form of the required features. The first scheme consists of couplers and circulators, while the second utilizes polarization handling elements to multiplex both signals, while a 100-m outdoor Free Space Optical link is utilized for both schemes. The configurations exhibit high stability, with uninterrupted transmission of traffic along the duration of the experiments, while the sensors’ performance is evaluated, with their discrepancies measured below 2%.","PeriodicalId":13065,"journal":{"name":"IEEE Photonics Technology Letters","volume":"37 9","pages":"528-531"},"PeriodicalIF":2.3,"publicationDate":"2025-03-24","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143839919","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}
{"title":"Efficient Scalable MoO3 Decorated PSi Based Optical Memristor Devices","authors":"Sharmila B;Ashutosh Kumar Dikshit;Priyanka Dwivedi","doi":"10.1109/LPT.2025.3554023","DOIUrl":"https://doi.org/10.1109/LPT.2025.3554023","url":null,"abstract":"This letter presents the development of wafer scalable optical memristor devices using molybdenum trioxide (MoO3) decorated porous silicon (PSi). The devices were tested with electrical and optical stimuli at room temperature. The test results have shown that the MoO3 decorated PSi based memristor offers improved performance metrics like high responsivity (826mA/W), high detectivity (<inline-formula> <tex-math>$1.08times 10^{mathbf {11}}$ </tex-math></inline-formula>Jones), fast response speed (84.1/<inline-formula> <tex-math>$80.1mu $ </tex-math></inline-formula>s), high paired pulse facilitation (PPF) index (461 %) and high endurance (100 cycles). The value of the responsivity is <inline-formula> <tex-math>$sim 3times 10^{mathbf {2}}$ </tex-math></inline-formula> times and ~4.5 times higher than PSi and MoO3 based devices respectively. The MoO3 decorated PSi device is highly repeatable, reliable and reproducible for ultrafast varying signals. These developed devices can be used for broadband light sensing as well as resistive switching applications.","PeriodicalId":13065,"journal":{"name":"IEEE Photonics Technology Letters","volume":"37 9","pages":"524-527"},"PeriodicalIF":2.3,"publicationDate":"2025-03-24","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143835370","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}
Eric D. Galván-Navarro;David Monzón-Hernández;Héctor Pérez-Aguilar;María del Socorro Hernández-Montes
{"title":"Optical Fiber Sensor for Monitoring the Vibration Modes of a Metallic Plate","authors":"Eric D. Galván-Navarro;David Monzón-Hernández;Héctor Pérez-Aguilar;María del Socorro Hernández-Montes","doi":"10.1109/LPT.2025.3553793","DOIUrl":"https://doi.org/10.1109/LPT.2025.3553793","url":null,"abstract":"In this work, we propose and demonstrate a frequency vibration sensor based on Multimode-Coreless-Multimode (MCM) fiber optic structure to measure the frequency of vibration modes of a metallic plate. To take advantage of the curvature sensitivity of the MCM structure, the device needs to be placed in direct contact with the structure under analysis, the vibration produces periodical changes in the curvature of the fiber that in turns modulate the intensity of the attenuation band of the MCM transmitted spectrum. In order to characterize the response of the sensor, we first measured the vibration frequencies of a loudspeaker in the range of 500 to 12500 Hz observing a percentage relative error less than 0.5 %. Then, the sensor was placed in contact with an aluminum plate of 5 cm x 5 cm x 0.3 cm. It was possible to detect the frequency of several vibration modes of the plate in a very simple way. The curvature-sensitive MCM structure is simple, easy to build, and sturdy, these features make the device a good candidate for measuring mechanical vibrations of an object.","PeriodicalId":13065,"journal":{"name":"IEEE Photonics Technology Letters","volume":"37 8","pages":"457-460"},"PeriodicalIF":2.3,"publicationDate":"2025-03-21","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"143740164","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}