Pub Date : 2025-11-12DOI: 10.1109/JPHOT.2025.3631821
Jianjun Ding;Chao Zhang;Niansong Liu;Zhongxu Wu;Chao Sun
To address the low sensitivity, poor selectivity and insufficient real-time response of conventional gas-detection techniques when analyzing complex gas mixtures, this study proposed a precise qualitative–quantitative system for multi-component trace gases that integrates photoacoustic spectroscopy (PAS) with advanced machine-learning algorithms. The setup employs a high-power infrared laser and a high-sensitivity cantilever-type photoacoustic cell. An Adaboost-enhanced improving support vector machine (Adaboost-ISVM) classifier was developed, achieving a classification accuracy of 99.17% for multi-component gases, with a Kappa coefficient of 99% and an AUC value of 99.375% for C2H2, NO2 and SF6 mixtures, significantly outperforming traditional SVM model. Additionally, to address the impact of temperature on detection results, this study introduced the Dung Beetle Optimizer (DBO) to optimize the Back Propagation (BP) neural network, it reduced the mean NO2 concentration prediction error to 0.29 ppm over 25–60 °C, superior to traditional BP, GA-BP and SSA-BP. The integrated system offers a robust solution for real-time, reliable trace-gas monitoring in complex industrial environments.
{"title":"Photoacoustic Spectroscopy-Based Multi-Component Gas Detection Empowered by Machine Learning","authors":"Jianjun Ding;Chao Zhang;Niansong Liu;Zhongxu Wu;Chao Sun","doi":"10.1109/JPHOT.2025.3631821","DOIUrl":"https://doi.org/10.1109/JPHOT.2025.3631821","url":null,"abstract":"To address the low sensitivity, poor selectivity and insufficient real-time response of conventional gas-detection techniques when analyzing complex gas mixtures, this study proposed a precise qualitative–quantitative system for multi-component trace gases that integrates photoacoustic spectroscopy (PAS) with advanced machine-learning algorithms. The setup employs a high-power infrared laser and a high-sensitivity cantilever-type photoacoustic cell. An Adaboost-enhanced improving support vector machine (Adaboost-ISVM) classifier was developed, achieving a classification accuracy of 99.17% for multi-component gases, with a Kappa coefficient of 99% and an AUC value of 99.375% for C<sub>2</sub>H<sub>2</sub>, NO<sub>2</sub> and SF<sub>6</sub> mixtures, significantly outperforming traditional SVM model. Additionally, to address the impact of temperature on detection results, this study introduced the Dung Beetle Optimizer (DBO) to optimize the Back Propagation (BP) neural network, it reduced the mean NO<sub>2</sub> concentration prediction error to 0.29 ppm over 25–60 °C, superior to traditional BP, GA-BP and SSA-BP. The integrated system offers a robust solution for real-time, reliable trace-gas monitoring in complex industrial environments.","PeriodicalId":13204,"journal":{"name":"IEEE Photonics Journal","volume":"17 6","pages":"1-12"},"PeriodicalIF":2.4,"publicationDate":"2025-11-12","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://ieeexplore.ieee.org/stamp/stamp.jsp?tp=&arnumber=11244114","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145560755","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}
Pub Date : 2025-11-11DOI: 10.1109/JPHOT.2025.3631724
Fanghua Li;Xiaolin Zhou;Yongkang Chen
We investigate detection for practical photon-counting receivers in underwater optical wireless communication (UOWC) systems, where dead-time effects and multi-user interference (MUI) pose significant challenges. In this paper, we propose an iterative detection method for multi-user uplink UOWC with signal-dependent shot noise, finite sampling rates, and thermal noise. We design a sparse interleaver and construct a sparse factor graph dedicated to the low-photon regime of non-perfect photon-counting systems, improving noise resilience, mitigating MUI, and enhance detection performance. We also employ iterative multi-user detection (MUD) based on a robust maximum a posteriori probability framework to address the photomultiplier tube (PMT) dead-time effects. Simulation results show that the proposed method achieves up to 5 dB bit error rate (BER) gains over conventional photon-counting schemes and maintains robust performance under diverse channel and noise conditions.
{"title":"An Underwater Multi-User Communication System Using Photomultiplier-Tube-Based Photon Detector With Dead-Time Effect and Shot Noise","authors":"Fanghua Li;Xiaolin Zhou;Yongkang Chen","doi":"10.1109/JPHOT.2025.3631724","DOIUrl":"https://doi.org/10.1109/JPHOT.2025.3631724","url":null,"abstract":"We investigate detection for practical photon-counting receivers in underwater optical wireless communication (UOWC) systems, where dead-time effects and multi-user interference (MUI) pose significant challenges. In this paper, we propose an iterative detection method for multi-user uplink UOWC with signal-dependent shot noise, finite sampling rates, and thermal noise. We design a sparse interleaver and construct a sparse factor graph dedicated to the low-photon regime of non-perfect photon-counting systems, improving noise resilience, mitigating MUI, and enhance detection performance. We also employ iterative multi-user detection (MUD) based on a robust maximum a posteriori probability framework to address the photomultiplier tube (PMT) dead-time effects. Simulation results show that the proposed method achieves up to 5 dB bit error rate (BER) gains over conventional photon-counting schemes and maintains robust performance under diverse channel and noise conditions.","PeriodicalId":13204,"journal":{"name":"IEEE Photonics Journal","volume":"18 1","pages":"1-8"},"PeriodicalIF":2.4,"publicationDate":"2025-11-11","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://ieeexplore.ieee.org/stamp/stamp.jsp?tp=&arnumber=11240108","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145830831","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}
Pub Date : 2025-11-11DOI: 10.1109/JPHOT.2025.3631635
Wei-Wen Hu
This paper presents a low-complexity, low-peak-to-average power ratio (PAPR) transmission scheme for discrete Hartley transform (DHT)-based underwater optical wireless communication (UOWC) systems, termed LPC-DHT-OFDM. The proposed scheme reduces transmitter complexity and mitigates nonlinear distortion by separately processing the real and imaginary parts of the modulated symbols. The real part is generated using multiply-accumulate and anti-symmetric operations, while the imaginary part is produced through a repetition-based method, thereby eliminating conventional DHT/IDHT operations. Non-negative signals are obtained through zero-level clipping and DC biasing and are transmitted simultaneously via two LEDs. As a member of the DHT-spread OFDM family, LPC-DHT-OFDM achieves substantial reductions in both PAPR and computational complexity, making it a promising candidate for practical UOWC applications. In addition, this paper provides the numerical analysis of its spectral efficiency, electrical and optical power requirements, PAPR, bit error rate, and computational complexity.
{"title":"Low-PAPR and Low-Complexity Transmission Schemes for DHT-Based Underwater Optical Wireless Systems","authors":"Wei-Wen Hu","doi":"10.1109/JPHOT.2025.3631635","DOIUrl":"https://doi.org/10.1109/JPHOT.2025.3631635","url":null,"abstract":"This paper presents a low-complexity, low-peak-to-average power ratio (PAPR) transmission scheme for discrete Hartley transform (DHT)-based underwater optical wireless communication (UOWC) systems, termed LPC-DHT-OFDM. The proposed scheme reduces transmitter complexity and mitigates nonlinear distortion by separately processing the real and imaginary parts of the modulated symbols. The real part is generated using multiply-accumulate and anti-symmetric operations, while the imaginary part is produced through a repetition-based method, thereby eliminating conventional DHT/IDHT operations. Non-negative signals are obtained through zero-level clipping and DC biasing and are transmitted simultaneously via two LEDs. As a member of the DHT-spread OFDM family, LPC-DHT-OFDM achieves substantial reductions in both PAPR and computational complexity, making it a promising candidate for practical UOWC applications. In addition, this paper provides the numerical analysis of its spectral efficiency, electrical and optical power requirements, PAPR, bit error rate, and computational complexity.","PeriodicalId":13204,"journal":{"name":"IEEE Photonics Journal","volume":"17 6","pages":"1-11"},"PeriodicalIF":2.4,"publicationDate":"2025-11-11","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://ieeexplore.ieee.org/stamp/stamp.jsp?tp=&arnumber=11240153","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145674794","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}
Insect wing interference is highly sensitive to the membrane thickness and has shown remarkable potential to differentiate insect species, both ex vivo in laboratory settings and for free-flying insects in situ. While several studies have reported diversity of wing interference patterns, no study has linked this resonant coherent scattering from membranes to the goniometric scattering phase function. We present a combined spectral and goniometric study and demonstrate that resonant wavelengths for a species selectively communicate with the thin and flat wing membrane, whereas scattering at dissonant wavelengths to a greater extent arises from the tubular veins. This report lays the groundwork for a deeper understanding of range dependence in entomological lidar and insect differentiation based on spectral and modulation properties.
{"title":"Goniometric Investigation of Spectral Scattering From Insect Wings in Near Infrared","authors":"Emmanuel Kotu Robertson;Meng Li;Hampus Månefjord;Jadranka Rota;Nina Reistad;Mikkel Brydegaard","doi":"10.1109/JPHOT.2025.3628525","DOIUrl":"https://doi.org/10.1109/JPHOT.2025.3628525","url":null,"abstract":"Insect wing interference is highly sensitive to the membrane thickness and has shown remarkable potential to differentiate insect species, both <italic>ex vivo</i> in laboratory settings and for free-flying insects <italic>in situ</i>. While several studies have reported diversity of wing interference patterns, no study has linked this resonant coherent scattering from membranes to the goniometric scattering phase function. We present a combined spectral and goniometric study and demonstrate that resonant wavelengths for a species selectively communicate with the thin and flat wing membrane, whereas scattering at dissonant wavelengths to a greater extent arises from the tubular veins. This report lays the groundwork for a deeper understanding of range dependence in entomological lidar and insect differentiation based on spectral and modulation properties.","PeriodicalId":13204,"journal":{"name":"IEEE Photonics Journal","volume":"17 6","pages":"1-5"},"PeriodicalIF":2.4,"publicationDate":"2025-11-03","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://ieeexplore.ieee.org/stamp/stamp.jsp?tp=&arnumber=11224671","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145510236","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}
To achieve single-frame dynamic phase measurement, an error-free synchronous demodulation algorithm for two-dimensional pixelated spatial carrier interferograms based on the Butterworth low-pass filter is proposed. It can obtain relatively accurate phase distribution with only one interferograms and is suitable for different noises level. Initially, pixelated spatial carrier interferograms is constructed, and specifically designed complex reference wavefront is introduced to separate the low-frequency phase signal of interest from high-frequency components. Subsequently, the Butterworth filter with specific order is designed for precise low-pass filtering, enabling error-free wavefront phase extraction. Finally, the proposed algorithm is compared with the interpolated 4-step phase-shifting algorithm (I-4PSA). Simulation and experiments demonstrate that the proposed method achieves higher accuracy, functions as global algorithm that is insensitive to noise and phase-shift errors, and effectively avoids the resolution loss and detuning error.
{"title":"Synchronous Demodulation of Pixelated Carrier Frequency Interferograms With the Butterworth Low-Pass Filter","authors":"Zhouxuan He;Hubing Du;Yifan Wang;Chang Liu;Kexin Yin;Gaopeng Zhang","doi":"10.1109/JPHOT.2025.3624838","DOIUrl":"https://doi.org/10.1109/JPHOT.2025.3624838","url":null,"abstract":"To achieve single-frame dynamic phase measurement, an error-free synchronous demodulation algorithm for two-dimensional pixelated spatial carrier interferograms based on the Butterworth low-pass filter is proposed. It can obtain relatively accurate phase distribution with only one interferograms and is suitable for different noises level. Initially, pixelated spatial carrier interferograms is constructed, and specifically designed complex reference wavefront is introduced to separate the low-frequency phase signal of interest from high-frequency components. Subsequently, the Butterworth filter with specific order is designed for precise low-pass filtering, enabling error-free wavefront phase extraction. Finally, the proposed algorithm is compared with the interpolated 4-step phase-shifting algorithm (I-4PSA). Simulation and experiments demonstrate that the proposed method achieves higher accuracy, functions as global algorithm that is insensitive to noise and phase-shift errors, and effectively avoids the resolution loss and detuning error.","PeriodicalId":13204,"journal":{"name":"IEEE Photonics Journal","volume":"17 6","pages":"1-9"},"PeriodicalIF":2.4,"publicationDate":"2025-10-23","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://ieeexplore.ieee.org/stamp/stamp.jsp?tp=&arnumber=11215896","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145510237","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}
Encoded computational hyperspectral cameras, propelled by advances in compressed sensing theory, making both miniaturization and real-time hyperspectral imaging feasible. Spectral-encoded or spatial-encoded hyperspectral imaging strategy have limited numbers of design parameters in optical components, leading to severe ill-posedness in hyperspectral images reconstruction, which constrain overall imaging quality. However, spatial-spectral-encoded hyperspectral imaging strategy which simultaneously performs spatial and spectral encoding entailing more powerful modulation, alleviating ill-posed problems and improving the quality of hyperspectral images. In this paper, we present a co-modulation framework based on diffractive optical element (DOE) and Superposition Fabry–Perot (SFP) filter array for computational hyperspectral camera that integrates these two components with a transformer-based reconstruction network through end-to-end learning. The learned DOE and SFP filter encode the hyperspectral datacube on the sensor via phase and amplitude modulation, and the transformer-based network accurately reconstructs the images from sensor measurements. We conduct extensive simulations to analyze and validate the relatively contributions of the DOE, SFP filter, and transformer-based reconstruction algorithm to the significantly improved performance of hyperspectral image reconstruction across various ablation study models. We further investigate and identify the $mathbf {4times 4}$ SFP filter unit configuration as the most effective design for achieving a balance between spectral fidelity and spatial resolution. Our results show that the proposed system outperforms state-of-the-art methods in hyperspectral images reconstruction quality, excelling in both spatial and spectral detail recovery, and maintaining good performance against realistic noise levels.
{"title":"Computational Hyperspectral Camera Design Based on Co-Modulation of Diffractive Optical Element and Superposition Fabry-Perot Filter Array","authors":"Shiqi Feng;Xuquan Wang;Xiong Dun;Zhanshan Wang;Xinbin Cheng","doi":"10.1109/JPHOT.2025.3624799","DOIUrl":"https://doi.org/10.1109/JPHOT.2025.3624799","url":null,"abstract":"Encoded computational hyperspectral cameras, propelled by advances in compressed sensing theory, making both miniaturization and real-time hyperspectral imaging feasible. Spectral-encoded or spatial-encoded hyperspectral imaging strategy have limited numbers of design parameters in optical components, leading to severe ill-posedness in hyperspectral images reconstruction, which constrain overall imaging quality. However, spatial-spectral-encoded hyperspectral imaging strategy which simultaneously performs spatial and spectral encoding entailing more powerful modulation, alleviating ill-posed problems and improving the quality of hyperspectral images. In this paper, we present a co-modulation framework based on diffractive optical element (DOE) and Superposition Fabry–Perot (SFP) filter array for computational hyperspectral camera that integrates these two components with a transformer-based reconstruction network through end-to-end learning. The learned DOE and SFP filter encode the hyperspectral datacube on the sensor via phase and amplitude modulation, and the transformer-based network accurately reconstructs the images from sensor measurements. We conduct extensive simulations to analyze and validate the relatively contributions of the DOE, SFP filter, and transformer-based reconstruction algorithm to the significantly improved performance of hyperspectral image reconstruction across various ablation study models. We further investigate and identify the <inline-formula><tex-math>$mathbf {4times 4}$</tex-math></inline-formula> SFP filter unit configuration as the most effective design for achieving a balance between spectral fidelity and spatial resolution. Our results show that the proposed system outperforms state-of-the-art methods in hyperspectral images reconstruction quality, excelling in both spatial and spectral detail recovery, and maintaining good performance against realistic noise levels.","PeriodicalId":13204,"journal":{"name":"IEEE Photonics Journal","volume":"17 6","pages":"1-9"},"PeriodicalIF":2.4,"publicationDate":"2025-10-23","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://ieeexplore.ieee.org/stamp/stamp.jsp?tp=&arnumber=11215898","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145455800","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}
Pub Date : 2025-10-23DOI: 10.1109/JPHOT.2025.3624684
Lei Sun;Xilin Chen;Xiuqiang Diao;Shiyuan Zhang;Fei Dong
In the mining industry, underground workers are mandated to wear safety helmets due to numerous potential risks. However, due to that the complex and harsh environment of underground coal mines, the object images obtained by video surveillance systems suffer from challenges such as uneven lighting, small and easily obscured targets, and significant environmental interference. Consequently, most existing deep learning-based object detection methods encounter substantial difficulties in accurately, efficiently and timely detecting safety helmets in underground coal mine. These challenges include low detection accuracy, poor model robustness, and a contradiction between the enhancement of detection performance and increased computational consumption demands. Therefore, to address these limitations, this work investigates a new detection algorithm for coal mine safety helmet wearing based on YOLOv5s, named YOLOv5s-CBCG. Firstly, an enhanced feature extraction network named FEN-CA is developed by incorporating the coordinate attention mechanism, which contributes to gain more powerful feature extraction ability for small object and suppress the interference of background noise in small target images. Secondly, it designs a new feature fusion network named FFE-BCG to enhance the multi-scale feature fusion, and further improve the small object detection accuracy while reducing computational cost. Then, the strengthened feature extraction network and feature fusion network are used as the backbone and neck of YOLOv5s-CBCG, respectively. Finally, self-built M-Helmet dataset is used to conduct extensive experiments, and the results indicate that the YOLOv5s-CBCG can reach 95.90% mAP on M-Helmet dataset with less computational expense than YOLOv5s, which outperforms other comparative methods. Specifically, the mAP is 4% and 7.9% higher compared to the latest YOLOv11n and YOLOv12n algorithm.
{"title":"Improved YOLOv5s-CBCG Algorithm for Detecting Safety Helmets in Underground Coal Mines","authors":"Lei Sun;Xilin Chen;Xiuqiang Diao;Shiyuan Zhang;Fei Dong","doi":"10.1109/JPHOT.2025.3624684","DOIUrl":"https://doi.org/10.1109/JPHOT.2025.3624684","url":null,"abstract":"In the mining industry, underground workers are mandated to wear safety helmets due to numerous potential risks. However, due to that the complex and harsh environment of underground coal mines, the object images obtained by video surveillance systems suffer from challenges such as uneven lighting, small and easily obscured targets, and significant environmental interference. Consequently, most existing deep learning-based object detection methods encounter substantial difficulties in accurately, efficiently and timely detecting safety helmets in underground coal mine. These challenges include low detection accuracy, poor model robustness, and a contradiction between the enhancement of detection performance and increased computational consumption demands. Therefore, to address these limitations, this work investigates a new detection algorithm for coal mine safety helmet wearing based on YOLOv5s, named YOLOv5s-CBCG. Firstly, an enhanced feature extraction network named FEN-CA is developed by incorporating the coordinate attention mechanism, which contributes to gain more powerful feature extraction ability for small object and suppress the interference of background noise in small target images. Secondly, it designs a new feature fusion network named FFE-BCG to enhance the multi-scale feature fusion, and further improve the small object detection accuracy while reducing computational cost. Then, the strengthened feature extraction network and feature fusion network are used as the backbone and neck of YOLOv5s-CBCG, respectively. Finally, self-built M-Helmet dataset is used to conduct extensive experiments, and the results indicate that the YOLOv5s-CBCG can reach 95.90% mAP on M-Helmet dataset with less computational expense than YOLOv5s, which outperforms other comparative methods. Specifically, the mAP is 4% and 7.9% higher compared to the latest YOLOv11n and YOLOv12n algorithm.","PeriodicalId":13204,"journal":{"name":"IEEE Photonics Journal","volume":"17 6","pages":"1-15"},"PeriodicalIF":2.4,"publicationDate":"2025-10-23","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://ieeexplore.ieee.org/stamp/stamp.jsp?tp=&arnumber=11215625","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145455926","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}
This paper presents a cost-effective bidirectional communication system that integrates single-mode fiber (SMF), free-space optical (FSO), and a 5G new radio (NR) wireless links, employing FBG sensors. The sensors serve as wavelength selectors, which helps reduce system costs. This approach is simpler and more affordable than advanced filtering techniques, wavelength demultiplexers, and multiple distributed feedback laser diode sources. The system supports a downstream data rate of 120-Gb/s (3 × 40-Gb/s/100-GHz) using wavelength division multiplexing, while the upstream transmission supports 60-Gb/s (3 × 20-Gb/s/60-GHz). These data rates are transmitted over a 32 km SMF, a 1.6 km FSO, and a 25 m 5G NR wireless link. Experimental results show that removing the FBG sensor from the downstream receiver setup leads to significant signal degradation. Specifically, the bit error rate (BER) increases from 2.04×10−5 (λ4) to 4.68 × 10−4 (λ1) and 2.29×10−5 (λ5) to 5.75 × 10−4 (λ2). Similarly, the error vector magnitude (EVM) rises from 10.53% (λ4) to 11.57% (λ1) and 10.70% (λ5) to 11.70% (λ2). Moreover, the constellation patterns become less defined. Under foggy conditions, these issues become more severe, with BER and EVM increasing significantly. Thus, the presence of the FBG sensor in the downstream receiver setup improved system performance. This approach offers a cost-effective solution for expanding 5G NR coverage.
{"title":"Cost-Effective Bidirectional SMF-FSO-5G NR Wireless System Employing FBG Sensors","authors":"Stotaw Talbachew Hayle;Hai-Han Lu;Yen-Chen Chen;Wei-Zhi Jiang;Wei-Ting Huang;Jia-Hui Chou;Feng-Ti Chen;Chi-Hsiang Hsu","doi":"10.1109/JPHOT.2025.3623695","DOIUrl":"https://doi.org/10.1109/JPHOT.2025.3623695","url":null,"abstract":"This paper presents a cost-effective bidirectional communication system that integrates single-mode fiber (SMF), free-space optical (FSO), and a 5G new radio (NR) wireless links, employing FBG sensors. The sensors serve as wavelength selectors, which helps reduce system costs. This approach is simpler and more affordable than advanced filtering techniques, wavelength demultiplexers, and multiple distributed feedback laser diode sources. The system supports a downstream data rate of 120-Gb/s (3 × 40-Gb/s/100-GHz) using wavelength division multiplexing, while the upstream transmission supports 60-Gb/s (3 × 20-Gb/s/60-GHz). These data rates are transmitted over a 32 km SMF, a 1.6 km FSO, and a 25 m 5G NR wireless link. Experimental results show that removing the FBG sensor from the downstream receiver setup leads to significant signal degradation. Specifically, the bit error rate (BER) increases from 2.04×10<sup>−5</sup> (λ<sub>4</sub>) to 4.68 × 10<sup>−4</sup> (λ<sub>1</sub>) and 2.29×10<sup>−5</sup> (λ<sub>5</sub>) to 5.75 × 10<sup>−4</sup> (λ<sub>2</sub>). Similarly, the error vector magnitude (EVM) rises from 10.53% (λ<sub>4</sub>) to 11.57% (λ<sub>1</sub>) and 10.70% (λ<sub>5</sub>) to 11.70% (λ<sub>2</sub>). Moreover, the constellation patterns become less defined. Under foggy conditions, these issues become more severe, with BER and EVM increasing significantly. Thus, the presence of the FBG sensor in the downstream receiver setup improved system performance. This approach offers a cost-effective solution for expanding 5G NR coverage.","PeriodicalId":13204,"journal":{"name":"IEEE Photonics Journal","volume":"17 6","pages":"1-12"},"PeriodicalIF":2.4,"publicationDate":"2025-10-20","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://ieeexplore.ieee.org/stamp/stamp.jsp?tp=&arnumber=11208696","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145455969","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}
Pub Date : 2025-10-20DOI: 10.1109/JPHOT.2025.3624147
You-Cheng Lin;You-Xin Wang;Shih-Chang Hsu;Hsing-Yi Huang;Yueh-Hsun Yang;Yung-Hsuan Li;Kuan-Wei Hu;Gong-Ru Lin
Under the quantum key distribution with differential phase-shift-keying protocol, the ultimate stability of the system is limited by the residual wavelength drift of the quantum-key carrier and the polarization/refractive-index/physical-length fluctuations induced by environmental thermal disturbance. To permanently overcome such a shortcoming, a 1-bit-delayed interferometric fiberized decoder with ultrastable visibility maintenance and long-term immunity to environmental perturbations is demonstrated by employing all polarization-maintaining-fiber to construct an asymmetric-arm Mach-Zehnder interferometer, and surrounding such a delay-line interferometric decoder with a thermal-isolated sponge and a styrofoam container. Receiving the DPS-QKD bit-stream with a high sifting key rate and low bit-error ratio is approached by maintaining the high interfered visibility and eliminating the wavelength drift with a highly adiabatic package. Such an ultrastable long-term 1-bit-delay interferometric decoder is particularly suitable for the persistent DPS-QKD operation towards future commercialization.
{"title":"Long-Term Stable Polarized Adiabatic Interfered Decoder for Differential Phase Shift Quantum Key","authors":"You-Cheng Lin;You-Xin Wang;Shih-Chang Hsu;Hsing-Yi Huang;Yueh-Hsun Yang;Yung-Hsuan Li;Kuan-Wei Hu;Gong-Ru Lin","doi":"10.1109/JPHOT.2025.3624147","DOIUrl":"https://doi.org/10.1109/JPHOT.2025.3624147","url":null,"abstract":"Under the quantum key distribution with differential phase-shift-keying protocol, the ultimate stability of the system is limited by the residual wavelength drift of the quantum-key carrier and the polarization/refractive-index/physical-length fluctuations induced by environmental thermal disturbance. To permanently overcome such a shortcoming, a 1-bit-delayed interferometric fiberized decoder with ultrastable visibility maintenance and long-term immunity to environmental perturbations is demonstrated by employing all polarization-maintaining-fiber to construct an asymmetric-arm Mach-Zehnder interferometer, and surrounding such a delay-line interferometric decoder with a thermal-isolated sponge and a styrofoam container. Receiving the DPS-QKD bit-stream with a high sifting key rate and low bit-error ratio is approached by maintaining the high interfered visibility and eliminating the wavelength drift with a highly adiabatic package. Such an ultrastable long-term 1-bit-delay interferometric decoder is particularly suitable for the persistent DPS-QKD operation towards future commercialization.","PeriodicalId":13204,"journal":{"name":"IEEE Photonics Journal","volume":"17 6","pages":"1-8"},"PeriodicalIF":2.4,"publicationDate":"2025-10-20","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://ieeexplore.ieee.org/stamp/stamp.jsp?tp=&arnumber=11208789","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145510238","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}
Pub Date : 2025-10-20DOI: 10.1109/JPHOT.2025.3624017
Ying Du;Jingyuan Wang;Zhiyong Xu;Jianhua Li
Although Modulating retro-reflector (MRR) technology offers a promising low-power solution for underwater wireless optical communication (UWOC), its performance under challenging oceanic turbulence has not been comprehensively analyzed. This paper addresses this gap by developing a robust model for an MRR-UWOC system operating through a turbulent channel. This paper derives the joint probability density function (PDF) for the turbulence-induced fading of the MRR-UWOC link based on the Exponentiated Weibull (EW) distribution and the generalized oceanic turbulence optical power spectrum (OTOPS) model. Utilizing this PDF, we obtain an approximate analytical expression for the average bit error rate (BER) of an on-off keying (OOK) system using the Gauss-Hermite quadrature method. Analysis of the turbulence confirms that aperture averaging mitigates fading and reveals a supersaturation effect. This analysis also indicates that the system is more sensitive to temperature variations than to salinity fluctuations. Furthermore, a comprehensive MRR UWOC model incorporating path loss from absorption and scattering reveals that these factors play fundamentally different roles: turbulence establishes a theoretical performance floor, while path loss imposes a power penalty on this baseline. The established model offers valuable guidance for the practical design and optimization of underwater optical networks.
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