Pub Date : 2025-12-01DOI: 10.1109/JPHOT.2025.3638782
Junnan Wang;Qihui He;Xiasi Sun;Lei Hou
With the rapid advancement of terahertz (THz) technology, there is an urgent demand for highly sensitive, broadband THz detectors that can operate at room temperature to support the evolving applications. Due to the high sensitivity of Rydberg atoms to external electric fields, detectors based on Rydberg quantum coherence offer great potential for high-performance THz detection. This paper proposed a ambient temperature electrometry approach for THz detection using probe laser spectroscopy of Rb Rydberg atoms and carry out a comprehensive study of a four-level system involving electromagnetically induced transparency (EIT) and Autler-Townes (AT) splitting in Rb cascades. By solving the Lindblad master equation, the influences of the THz electric field, probe laser, and coupling laser on the populations of the ground and Rydberg states were analyzed. Furthermore, the effects of temperature and vapor cell dimensions on the Rb atomic density are examined, revealing their critical impact on detection sensitivity. The results predict that the proposed quantum coherence based THz detection method can achieve a sensitivity as low as 10$^{-9}$ V/m/Hz$^{1/2}$ at ambient temperature. This paper provides a solid theoretical foundation for the implementation and optimization of Rydberg-atom-based quantum coherence techniques for high-sensitivity, ambient temperature THz wave detection.
{"title":"High Sensitive Quantum Coherent THz Electrometry With Four-Level Rydberg Atoms","authors":"Junnan Wang;Qihui He;Xiasi Sun;Lei Hou","doi":"10.1109/JPHOT.2025.3638782","DOIUrl":"https://doi.org/10.1109/JPHOT.2025.3638782","url":null,"abstract":"With the rapid advancement of terahertz (THz) technology, there is an urgent demand for highly sensitive, broadband THz detectors that can operate at room temperature to support the evolving applications. Due to the high sensitivity of Rydberg atoms to external electric fields, detectors based on Rydberg quantum coherence offer great potential for high-performance THz detection. This paper proposed a ambient temperature electrometry approach for THz detection using probe laser spectroscopy of Rb Rydberg atoms and carry out a comprehensive study of a four-level system involving electromagnetically induced transparency (EIT) and Autler-Townes (AT) splitting in Rb cascades. By solving the Lindblad master equation, the influences of the THz electric field, probe laser, and coupling laser on the populations of the ground and Rydberg states were analyzed. Furthermore, the effects of temperature and vapor cell dimensions on the Rb atomic density are examined, revealing their critical impact on detection sensitivity. The results predict that the proposed quantum coherence based THz detection method can achieve a sensitivity as low as 10<inline-formula><tex-math>$^{-9}$</tex-math></inline-formula> V/m/Hz<inline-formula><tex-math>$^{1/2}$</tex-math></inline-formula> at ambient temperature. This paper provides a solid theoretical foundation for the implementation and optimization of Rydberg-atom-based quantum coherence techniques for high-sensitivity, ambient temperature THz wave detection.","PeriodicalId":13204,"journal":{"name":"IEEE Photonics Journal","volume":"18 1","pages":"1-6"},"PeriodicalIF":2.4,"publicationDate":"2025-12-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://ieeexplore.ieee.org/stamp/stamp.jsp?tp=&arnumber=11271520","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145830810","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}
An optical phased array (OPA) is a device capable of forming and scanning arbitrary optical beams without any mechanical moving parts. We are developing an OPA using organic electro-optic (EO) polymers that exhibit ultrahigh speed and low power consumption. The deflection angle of an OPA depends on the pitch of the waveguide’s output section; thus, a narrower pitch is required to increase the deflection angle. Here, we propose an organic–inorganic dual-layer OPA that uses EO polymer waveguides as phase shifters and silicon nitride (SiN) waveguides as the output section. Because SiN has a higher refractive index than the EO polymer, it provides strong optical confinement, enabling a narrower waveguide pitch. This study describes a transition section designed to transfer light between the EO polymer waveguide and SiN waveguides. Numerical calculations show that a transition section with tapered SiN waveguides achieves a coupling loss of 0.76 dB, while experimental measurements indicate a coupling loss of 1.67 dB. Optical experiments on devices fabricated via a layering process demonstrated a beam divergence angle of 1.917$^{circ}$ and a maximum deflection angle of 36.64$^{circ}$ from optical beams emitted by a SiN grating array with a 2.5 $mu$m pitch at the emission section.
{"title":"Optical Phased Array With Dual-Layer Electro-Optic Polymer and Silicon Nitride Waveguides","authors":"Yuji Miyamoto;Masato Miura;Junichi Shibasaki;Masakazu Nanba;Kenji Machida;Rieko Ueda;Takahiro Kaji;Toshiki Yamada;Akira Otomo;Yoshikuni Hirano","doi":"10.1109/JPHOT.2025.3639001","DOIUrl":"https://doi.org/10.1109/JPHOT.2025.3639001","url":null,"abstract":"An optical phased array (OPA) is a device capable of forming and scanning arbitrary optical beams without any mechanical moving parts. We are developing an OPA using organic electro-optic (EO) polymers that exhibit ultrahigh speed and low power consumption. The deflection angle of an OPA depends on the pitch of the waveguide’s output section; thus, a narrower pitch is required to increase the deflection angle. Here, we propose an organic–inorganic dual-layer OPA that uses EO polymer waveguides as phase shifters and silicon nitride (SiN) waveguides as the output section. Because SiN has a higher refractive index than the EO polymer, it provides strong optical confinement, enabling a narrower waveguide pitch. This study describes a transition section designed to transfer light between the EO polymer waveguide and SiN waveguides. Numerical calculations show that a transition section with tapered SiN waveguides achieves a coupling loss of 0.76 dB, while experimental measurements indicate a coupling loss of 1.67 dB. Optical experiments on devices fabricated via a layering process demonstrated a beam divergence angle of <bold>1.917<inline-formula><tex-math>$^{circ}$</tex-math></inline-formula></b> and a maximum deflection angle of <bold>36.64<inline-formula><tex-math>$^{circ}$</tex-math></inline-formula></b> from optical beams emitted by a SiN grating array with a <bold>2.5 <inline-formula><tex-math>$mu$</tex-math></inline-formula>m</b> pitch at the emission section.","PeriodicalId":13204,"journal":{"name":"IEEE Photonics Journal","volume":"18 1","pages":"1-8"},"PeriodicalIF":2.4,"publicationDate":"2025-12-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://ieeexplore.ieee.org/stamp/stamp.jsp?tp=&arnumber=11271590","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145830945","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 : 2025-11-25DOI: 10.1109/JPHOT.2025.3636909
Bo Gao;Jia-Ning Guo;Jian Zhang;Yan-Yu Zhang;Dun Li
Visible light communication (VLC) integrates illumination and communication, offering significant potential for 6G mobile communications. In 6G communications, reliability and low latency are critical. To meet these demands, finite blocklength codewords are employed for data transmission. For indoor VLC scenarios, multiple light-emitting diodes (LEDs) serve as transmitters, with each transmitter operating under distinct optical power constraints tailored to user requirements. In this paper, a multidimensional constellation design based on geometric shaping is proposed for multi-input single-output (MISO) VLC with per-LED optical power constraints. This design employs truncated cubic shaping to design the equivalent transmitted signal and decomposes it into transmitted signals using a partition-based greedy decomposition. The proposed scheme designs signals in the finite blocklength regime while adhering to per-LED optical power constraints. Simulation results for indoor MISO VLC systems demonstrate the advantages of the proposed scheme over benchmark schemes and quantify the performance gains as well as the gap to the Shannon limit.
{"title":"Multidimensional Constellation Design Based on Geometric Shaping for MISO VLC With Per-LED Optical Power Constraints","authors":"Bo Gao;Jia-Ning Guo;Jian Zhang;Yan-Yu Zhang;Dun Li","doi":"10.1109/JPHOT.2025.3636909","DOIUrl":"https://doi.org/10.1109/JPHOT.2025.3636909","url":null,"abstract":"Visible light communication (VLC) integrates illumination and communication, offering significant potential for 6G mobile communications. In 6G communications, reliability and low latency are critical. To meet these demands, finite blocklength codewords are employed for data transmission. For indoor VLC scenarios, multiple light-emitting diodes (LEDs) serve as transmitters, with each transmitter operating under distinct optical power constraints tailored to user requirements. In this paper, a multidimensional constellation design based on geometric shaping is proposed for multi-input single-output (MISO) VLC with per-LED optical power constraints. This design employs truncated cubic shaping to design the equivalent transmitted signal and decomposes it into transmitted signals using a partition-based greedy decomposition. The proposed scheme designs signals in the finite blocklength regime while adhering to per-LED optical power constraints. Simulation results for indoor MISO VLC systems demonstrate the advantages of the proposed scheme over benchmark schemes and quantify the performance gains as well as the gap to the Shannon limit.","PeriodicalId":13204,"journal":{"name":"IEEE Photonics Journal","volume":"17 6","pages":"1-10"},"PeriodicalIF":2.4,"publicationDate":"2025-11-25","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://ieeexplore.ieee.org/stamp/stamp.jsp?tp=&arnumber=11267212","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145674808","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}
An isolation apparatus for far-infrared wavelengths was developed and integrated into a CO2 nanosecond laser system for performance evaluation. The apparatus uses a dual acousto-optic modulator (AOM) configuration combined with an image-relaying delay line to achieve high isolation of back-reflected light. This design is based on the Bragg diffraction mechanism of the AOMs to achieve a high isolation for back-reflected radiation along the primary optical path. The delay line’s extended propagation distance and image-relaying properties effectively compensate for the slow switching speeds of the AOMs. Experimental investigation within the CO2 nanosecond laser system demonstrates an isolation of 31.82 dB for back-reflected light, with output beam quality factors of MX2 = 1.070 and MY2 = 1.017, an overall transmittance of 35.73%, and a power-handling capability exceeding 130.60 W.
{"title":"An Isolation Apparatus for CO2 Nanosecond Laser Systems","authors":"Zhaowang Ma;Yiming Cai;Yicheng Zhou;Zejun Li;Junping Guo;Lingyu Liu;Xudong Jin;Yang Bu;Xing Ding;Qing Ye;Peng Zhang;Haiwen Cai","doi":"10.1109/JPHOT.2025.3636570","DOIUrl":"https://doi.org/10.1109/JPHOT.2025.3636570","url":null,"abstract":"An isolation apparatus for far-infrared wavelengths was developed and integrated into a CO<sub>2</sub> nanosecond laser system for performance evaluation. The apparatus uses a dual acousto-optic modulator (AOM) configuration combined with an image-relaying delay line to achieve high isolation of back-reflected light. This design is based on the Bragg diffraction mechanism of the AOMs to achieve a high isolation for back-reflected radiation along the primary optical path. The delay line’s extended propagation distance and image-relaying properties effectively compensate for the slow switching speeds of the AOMs. Experimental investigation within the CO<sub>2</sub> nanosecond laser system demonstrates an isolation of 31.82 dB for back-reflected light, with output beam quality factors of M<sub>X</sub><sup>2</sup> = 1.070 and M<sub>Y</sub><sup>2</sup> = 1.017, an overall transmittance of 35.73%, and a power-handling capability exceeding 130.60 W.","PeriodicalId":13204,"journal":{"name":"IEEE Photonics Journal","volume":"18 1","pages":"1-7"},"PeriodicalIF":2.4,"publicationDate":"2025-11-24","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://ieeexplore.ieee.org/stamp/stamp.jsp?tp=&arnumber=11267047","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145886617","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 : 2025-11-24DOI: 10.1109/JPHOT.2025.3636561
Jia Feng;Yang Liu;Cheng Li;Kui Shi;Zhujie Liang;Hao Wang
Reconstructing high-quality image at low measurement rates remains a primary objective for single-pixel imaging (SPI). Deep learning-based compression reconstruction algorithm can improve the quality and reconstruction speed of the reconstructed image. Generative adversarial network (GAN) and diffusion model (DM), which have excellent performance in the field of image generation have achieved excellent research results in the field of single-pixel imaging reconstruction. GAN-based models often suffer from the mode collapse problem, and the diffusion model relies on multi-step iteration to obtain a fine and smooth forward diffusion process, but its lengthy sampling process limits the reconstruction efficiency. Therefore, we propose a single-pixel imaging reconstruction algorithm EDGN that combines the advantages of the two generation models. The generative adversarial network uses the measurement and noise to generate the initial image, the denoising diffusion probability model is used to optimize the image refinement, and the high-quality reconstructed image is obtained by joint training. Besides, an adaptive regularization coefficient limited range adjustment method (ARCLA) is designed to achieve fast convergence of coefficients. Simulations and experiments confirm that our proposed enhanced dual generative network method can significantly improve the quality of image reconstruction at low measurement rates.
{"title":"Single Pixel Imaging Based on Enhanced Dual Generative Networks","authors":"Jia Feng;Yang Liu;Cheng Li;Kui Shi;Zhujie Liang;Hao Wang","doi":"10.1109/JPHOT.2025.3636561","DOIUrl":"https://doi.org/10.1109/JPHOT.2025.3636561","url":null,"abstract":"Reconstructing high-quality image at low measurement rates remains a primary objective for single-pixel imaging (SPI). Deep learning-based compression reconstruction algorithm can improve the quality and reconstruction speed of the reconstructed image. Generative adversarial network (GAN) and diffusion model (DM), which have excellent performance in the field of image generation have achieved excellent research results in the field of single-pixel imaging reconstruction. GAN-based models often suffer from the mode collapse problem, and the diffusion model relies on multi-step iteration to obtain a fine and smooth forward diffusion process, but its lengthy sampling process limits the reconstruction efficiency. Therefore, we propose a single-pixel imaging reconstruction algorithm EDGN that combines the advantages of the two generation models. The generative adversarial network uses the measurement and noise to generate the initial image, the denoising diffusion probability model is used to optimize the image refinement, and the high-quality reconstructed image is obtained by joint training. Besides, an adaptive regularization coefficient limited range adjustment method (ARCLA) is designed to achieve fast convergence of coefficients. Simulations and experiments confirm that our proposed enhanced dual generative network method can significantly improve the quality of image reconstruction at low measurement rates.","PeriodicalId":13204,"journal":{"name":"IEEE Photonics Journal","volume":"17 6","pages":"1-12"},"PeriodicalIF":2.4,"publicationDate":"2025-11-24","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://ieeexplore.ieee.org/stamp/stamp.jsp?tp=&arnumber=11267056","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145674810","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}
We propose a novel filter scheme to enhance the sensing accuracy of phase-sensitive optical frequency domain reflectometer (Φ-OFDR) while maintaining high spatial resolution via cascading Hampel filter and median filter. The working principle is theoretically analyzed and optimal filtering parameters are analyzed with the practical experimental configuration. Experimental results demonstrate that the proposed method achieves a temperature accuracy of 0.49 °C, indicating a 28 dB enhancement compared with the raw data while maintaining 4.6 mm spatial resolution. Compared to other conventional filtering methods applied in Φ-OFDR, the proposed hybrid Hampel-Median filter yields about 2∼4 times improvement in sensing accuracy and increases SNR by more than 5 dB with consistent spatial resolution condition. On the other hand, the proposed filtering method enhances the spatial resolution about 2∼6 times with the same sensing accuracy. The experimental results reveal that the novel filtering approach enables high sensing accuracy and spatial resolution for the distributed temperature or strain sensing scenarios of Φ-OFDR, without any hardware modifications.
{"title":"Sensing Accuracy Enhancement of Phase-Sensitive Optical Frequency Domain Reflectometry Using Hybrid Hampel-Median Filter","authors":"Yiheng Cheng;Qinlin Zeng;Fei Liu;Fei Cui;Zhi Wang;Dan Li;Benzhang Wang;Xian Zhou","doi":"10.1109/JPHOT.2025.3635712","DOIUrl":"https://doi.org/10.1109/JPHOT.2025.3635712","url":null,"abstract":"We propose a novel filter scheme to enhance the sensing accuracy of phase-sensitive optical frequency domain reflectometer (Φ-OFDR) while maintaining high spatial resolution via cascading Hampel filter and median filter. The working principle is theoretically analyzed and optimal filtering parameters are analyzed with the practical experimental configuration. Experimental results demonstrate that the proposed method achieves a temperature accuracy of 0.49 °C, indicating a 28 dB enhancement compared with the raw data while maintaining 4.6 mm spatial resolution. Compared to other conventional filtering methods applied in Φ-OFDR, the proposed hybrid Hampel-Median filter yields about 2∼4 times improvement in sensing accuracy and increases SNR by more than 5 dB with consistent spatial resolution condition. On the other hand, the proposed filtering method enhances the spatial resolution about 2∼6 times with the same sensing accuracy. The experimental results reveal that the novel filtering approach enables high sensing accuracy and spatial resolution for the distributed temperature or strain sensing scenarios of Φ-OFDR, without any hardware modifications.","PeriodicalId":13204,"journal":{"name":"IEEE Photonics Journal","volume":"17 6","pages":"1-9"},"PeriodicalIF":2.4,"publicationDate":"2025-11-21","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://ieeexplore.ieee.org/stamp/stamp.jsp?tp=&arnumber=11264304","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145674809","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 : 2025-11-17DOI: 10.1109/jphot.2025.3633421
Yujie Qiu, Luzhou Wang, Zichun Le
Microfluidics is expected to replace traditional medical detection methods as the next generation medical detection technology due to its high throughput, less sample required, and fast mass transfer. However, microfluidic chips mostly need a peristaltic pump to provide pressure to feed the sample, which limits its capability of immediate detection as well as portability. In this paper, a gravity-driven droplet-based microfluidic multiplexed Raman sensor has been developed, which is applicable to both rigid and flexible substrates. Furthermore, the fabrication method is also proposed. The developed gravity-driven multiplexed Raman sensor is easy to manufacture, thin, cheap and does not require external energy input. The performance of the developed sensor was characterized by using malachite green, and the minimum 10-8 mol/L malachite green can be detected with 633 nm laser irradiation. Moreover, we optimized its dimensions, while retaining its excellent features such as easy fabrication, cost-effectiveness and thinness. The proposed sensor provides a new view for portable on-chip detection of liquid droplets.
{"title":"Highly Expandable Portable Gravity-Driven Multiplexable Raman Sensor","authors":"Yujie Qiu, Luzhou Wang, Zichun Le","doi":"10.1109/jphot.2025.3633421","DOIUrl":"https://doi.org/10.1109/jphot.2025.3633421","url":null,"abstract":"Microfluidics is expected to replace traditional medical detection methods as the next generation medical detection technology due to its high throughput, less sample required, and fast mass transfer. However, microfluidic chips mostly need a peristaltic pump to provide pressure to feed the sample, which limits its capability of immediate detection as well as portability. In this paper, a gravity-driven droplet-based microfluidic multiplexed Raman sensor has been developed, which is applicable to both rigid and flexible substrates. Furthermore, the fabrication method is also proposed. The developed gravity-driven multiplexed Raman sensor is easy to manufacture, thin, cheap and does not require external energy input. The performance of the developed sensor was characterized by using malachite green, and the minimum 10-8 mol/L malachite green can be detected with 633 nm laser irradiation. Moreover, we optimized its dimensions, while retaining its excellent features such as easy fabrication, cost-effectiveness and thinness. The proposed sensor provides a new view for portable on-chip detection of liquid droplets.","PeriodicalId":13204,"journal":{"name":"IEEE Photonics Journal","volume":"17 6","pages":"1-7"},"PeriodicalIF":0.0,"publicationDate":"2025-11-17","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"147333356","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 : 2025-11-12DOI: 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}
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