Pub Date : 2024-07-02DOI: 10.1109/JPHOT.2024.3421574
Jian Lin;Qiurong Yan;Quan Zou;Shida Sun;Zhen Wei;Hua Du
Single-pixel imaging is an advanced computational imaging technique based on compressive sensing that offers higher signal-to-noise ratio and broader application scope compared to traditional imaging techniques. However, conventional reconstruction algorithms suffer from issues such as long processing time and low reconstruction accuracy during the sampling and reconstruction processes. Deep learning-based compressed reconstruction networks can circumvent the complex iterative computations of traditional algorithms and achieve fast, high-quality reconstruction. In this paper, we propose a Variational Multi-Scale Error Compensation Network (VMSE) based on variational autoencoders. VMSE designs an error compensation network to enhance the feature representation capability of the sampling reconstruction network. We employ multiple latent variables to generate error features at different scales in the intermediate layers of the error compensation network, compensating the reconstructed image. Additionally, we design a module that simultaneously learns in the spatial and frequency domains, which is used for upsampling and complementing the missing high-frequency information in the frequency domain. On the MNIST dataset, when the sampling rate is 0.025, VMSE achieved higher Peak Signal-to-Noise Ratio(PSNR) and Structural Similarity Index(SSIM) scores, especially with an SSIM score of 0.963, significantly surpassing Reconnet and DR2Net's scores of 0.930 and 0.920, respectively. This was further corroborated by practical experiments, where at low sampling rates, VMSE could reconstruct outlines more clearly compared to TVAL3.
{"title":"A Variational Multi-Scale Error Compensation Network for Single-Pixel Imaging","authors":"Jian Lin;Qiurong Yan;Quan Zou;Shida Sun;Zhen Wei;Hua Du","doi":"10.1109/JPHOT.2024.3421574","DOIUrl":"10.1109/JPHOT.2024.3421574","url":null,"abstract":"Single-pixel imaging is an advanced computational imaging technique based on compressive sensing that offers higher signal-to-noise ratio and broader application scope compared to traditional imaging techniques. However, conventional reconstruction algorithms suffer from issues such as long processing time and low reconstruction accuracy during the sampling and reconstruction processes. Deep learning-based compressed reconstruction networks can circumvent the complex iterative computations of traditional algorithms and achieve fast, high-quality reconstruction. In this paper, we propose a Variational Multi-Scale Error Compensation Network (VMSE) based on variational autoencoders. VMSE designs an error compensation network to enhance the feature representation capability of the sampling reconstruction network. We employ multiple latent variables to generate error features at different scales in the intermediate layers of the error compensation network, compensating the reconstructed image. Additionally, we design a module that simultaneously learns in the spatial and frequency domains, which is used for upsampling and complementing the missing high-frequency information in the frequency domain. On the MNIST dataset, when the sampling rate is 0.025, VMSE achieved higher Peak Signal-to-Noise Ratio(PSNR) and Structural Similarity Index(SSIM) scores, especially with an SSIM score of 0.963, significantly surpassing Reconnet and DR2Net's scores of 0.930 and 0.920, respectively. This was further corroborated by practical experiments, where at low sampling rates, VMSE could reconstruct outlines more clearly compared to TVAL3.","PeriodicalId":13204,"journal":{"name":"IEEE Photonics Journal","volume":"16 4","pages":"1-11"},"PeriodicalIF":2.1,"publicationDate":"2024-07-02","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://ieeexplore.ieee.org/stamp/stamp.jsp?tp=&arnumber=10582416","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141514969","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}
A transmission line (TL) impedance transformer of through-hole (TO)-CAN distributed feedback (DFB) laser is proposed and fabricated. The gain and noise factor (NF) of analog optical link can be improved by optimizing the laser impedance matching network. The radio frequency (RF) package of DFB is optimized to extend bandwidth and reduce return loss. In this paper, a flexible printed circuit (FPC) with low-loss impedance matching network is designed to improved the RF characteristics of TO-CAN DFB laser. The return path between FPC and TO-CAN is optimized to eliminate microwave resonances. The small signal model of an analog optical link is analyzed in detail. The measured frequency response of the TO-CAN DFB is 18.4 GHz. The microwave reflection is below −10 dB. The measured results correlates perfectly with the simulated results. The gain of analog optical link is increased by 3 dB. The NF is also reduced by about 2.5 dB.
{"title":"A TO-CAN DFB Laser With Transmission Line Impedance Transformer for Analog Optical Link","authors":"Congbiao Lei;Yuxuan Jiang;Guangcheng Zhong;Liang Xie","doi":"10.1109/JPHOT.2024.3422269","DOIUrl":"10.1109/JPHOT.2024.3422269","url":null,"abstract":"A transmission line (TL) impedance transformer of through-hole (TO)-CAN distributed feedback (DFB) laser is proposed and fabricated. The gain and noise factor (NF) of analog optical link can be improved by optimizing the laser impedance matching network. The radio frequency (RF) package of DFB is optimized to extend bandwidth and reduce return loss. In this paper, a flexible printed circuit (FPC) with low-loss impedance matching network is designed to improved the RF characteristics of TO-CAN DFB laser. The return path between FPC and TO-CAN is optimized to eliminate microwave resonances. The small signal model of an analog optical link is analyzed in detail. The measured frequency response of the TO-CAN DFB is 18.4 GHz. The microwave reflection is below −10 dB. The measured results correlates perfectly with the simulated results. The gain of analog optical link is increased by 3 dB. The NF is also reduced by about 2.5 dB.","PeriodicalId":13204,"journal":{"name":"IEEE Photonics Journal","volume":"16 6","pages":"1-6"},"PeriodicalIF":2.1,"publicationDate":"2024-07-02","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://ieeexplore.ieee.org/stamp/stamp.jsp?tp=&arnumber=10582283","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141514968","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 report on versatile orbital angular momentum beam generation through the association of a 61-channels coherent beam combining digital laser and a liquid-crystal q-plate. Particularly, high-order vortex beams that carry orbital angular momentum are generated with radial, azimuthal and/or circular polarization states. The q-plate is designed and manufactured to sustain high average power ensuring that the vortex spatial mode is preserved. The proposed system offers an extra degree of freedom for various applications requesting beam shaping with specific polarization state.
{"title":"Controlled Generation of Orbital Angular Momentum Beams With Coherent Beam Combining Digital Laser and Liquid-Crystal q-Plate","authors":"Corentin Lechevalier;Claude-Alban Ranély-Vergé-Dépré;Ihsan Fsaifes;Rezki Becheker;Gerben Boer;Jean-Christophe Chanteloup","doi":"10.1109/JPHOT.2024.3421244","DOIUrl":"10.1109/JPHOT.2024.3421244","url":null,"abstract":"We report on versatile orbital angular momentum beam generation through the association of a 61-channels coherent beam combining digital laser and a liquid-crystal q-plate. Particularly, high-order vortex beams that carry orbital angular momentum are generated with radial, azimuthal and/or circular polarization states. The q-plate is designed and manufactured to sustain high average power ensuring that the vortex spatial mode is preserved. The proposed system offers an extra degree of freedom for various applications requesting beam shaping with specific polarization state.","PeriodicalId":13204,"journal":{"name":"IEEE Photonics Journal","volume":"16 4","pages":"1-5"},"PeriodicalIF":2.1,"publicationDate":"2024-07-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://ieeexplore.ieee.org/stamp/stamp.jsp?tp=&arnumber=10578305","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141514970","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 : 2024-07-01DOI: 10.1109/JPHOT.2024.3421275
Jun Li;Ruixu Yao
This work utilizes the CEEMDAN algorithm to analyze the interference of Rayleigh back-scattering signals in standard communication optical fibers. The technology has several advantages, such as anti-electromagnetic interference, improved electrical insulation, corrosion resistance, higher sensitivity, and the capability for long-distance monitoring. In this study, in-situ monitoring data from a 53.2 km natural gas pipeline in a terrain area in Southwest China were analyzed. The results demonstrate that, using the CEEMDAN algorithm for a blind test conducted over fourteen days, a 100% recognition accuracy for mechanical tamping and a Nuisance Alarm Rate (NAR) of less than 1% were achieved.
{"title":"Field Deployment of Natural Gas Pipeline Pre-Warning System With CEEMDAN Denoising Method","authors":"Jun Li;Ruixu Yao","doi":"10.1109/JPHOT.2024.3421275","DOIUrl":"10.1109/JPHOT.2024.3421275","url":null,"abstract":"This work utilizes the CEEMDAN algorithm to analyze the interference of Rayleigh back-scattering signals in standard communication optical fibers. The technology has several advantages, such as anti-electromagnetic interference, improved electrical insulation, corrosion resistance, higher sensitivity, and the capability for long-distance monitoring. In this study, in-situ monitoring data from a 53.2 km natural gas pipeline in a terrain area in Southwest China were analyzed. The results demonstrate that, using the CEEMDAN algorithm for a blind test conducted over fourteen days, a 100% recognition accuracy for mechanical tamping and a Nuisance Alarm Rate (NAR) of less than 1% were achieved.","PeriodicalId":13204,"journal":{"name":"IEEE Photonics Journal","volume":"16 4","pages":"1-8"},"PeriodicalIF":2.1,"publicationDate":"2024-07-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://ieeexplore.ieee.org/stamp/stamp.jsp?tp=&arnumber=10578009","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141504565","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 : 2024-06-28DOI: 10.1109/JPHOT.2024.3420787
Quan Zou;Qiurong Yan;Qianling Dai;Ao Wang;Bo Yang;Yi Li;Jinwei Yan
Single-pixel imaging (SPI), an imaging technique based on the theory of compressed sensing, is limited in real-time imaging and high-resolution images due to its relatively slow imaging speed. In recent years, deep unfolding network compressed sensing reconstruction algorithms based on deep learning have proven to be an effective solution for faster and higher quality image reconstruction. However, existing deep unfolding networks mainly rely on a single piece of a priori information and may ignore other intrinsic structures of the image. Therefore, in this paper, we propose a deep unfolding network (MPDU-Net) that incorporates multiple prior information. To effectively fuse multiple prior information, we propose three different fusion strategies in the deep reconstruction sub-network. An unbiased convolutional layer is used to simulate the sampling reconstruction process to achieve joint reconstruction for effective removal of block artifacts. The sampling matrix is input into the deep reconstruction sub-network as a learnable parameter to achieve joint optimization of sampling reconstruction. Simulation and practical experimental results show that the proposed network outperforms existing compressed sensing reconstruction algorithms based on deep unfolding networks.
{"title":"Single Pixel Imaging Based on Multiple Prior Deep Unfolding Network","authors":"Quan Zou;Qiurong Yan;Qianling Dai;Ao Wang;Bo Yang;Yi Li;Jinwei Yan","doi":"10.1109/JPHOT.2024.3420787","DOIUrl":"10.1109/JPHOT.2024.3420787","url":null,"abstract":"Single-pixel imaging (SPI), an imaging technique based on the theory of compressed sensing, is limited in real-time imaging and high-resolution images due to its relatively slow imaging speed. In recent years, deep unfolding network compressed sensing reconstruction algorithms based on deep learning have proven to be an effective solution for faster and higher quality image reconstruction. However, existing deep unfolding networks mainly rely on a single piece of a priori information and may ignore other intrinsic structures of the image. Therefore, in this paper, we propose a deep unfolding network (MPDU-Net) that incorporates multiple prior information. To effectively fuse multiple prior information, we propose three different fusion strategies in the deep reconstruction sub-network. An unbiased convolutional layer is used to simulate the sampling reconstruction process to achieve joint reconstruction for effective removal of block artifacts. The sampling matrix is input into the deep reconstruction sub-network as a learnable parameter to achieve joint optimization of sampling reconstruction. Simulation and practical experimental results show that the proposed network outperforms existing compressed sensing reconstruction algorithms based on deep unfolding networks.","PeriodicalId":13204,"journal":{"name":"IEEE Photonics Journal","volume":"16 4","pages":"1-10"},"PeriodicalIF":2.1,"publicationDate":"2024-06-28","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://ieeexplore.ieee.org/stamp/stamp.jsp?tp=&arnumber=10577085","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141504708","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 : 2024-06-24DOI: 10.1109/JPHOT.2024.3418371
Wafaa M. R. Shakir;Ali S. Mahdi;Hani Hamdan;Jinan Charafeddine;Haitham Al Satai;Radouane Akrache;Samir Haddad;Jinane Sayah
In this article, we develop an innovative series representation for the sum of Rician non-zero boresight pointing error random variates based on the ${bm{kappa }} - {bm{mu }}$ distribution, which is suitable for multiple-input multiple-output (MIMO) transmission for the first time. Then, using this new representation, we introduce a novel closed-form probability density function (PDF) approximation for the sum of Gamma-Gamma random variates with generalized pointing errors and atmospheric attenuation of MIMO free-space optical (FSO) communications. Statistical Kolmogorov-Smirnov tests confirm the accuracy of this approximation over a wide range of channel conditions. The significance of this approximation is emphasized by deriving closed-form expressions for the ergodic capacity, outage probability, and average bit error rate (BER) using Meijer's G-function. This article provides a comprehensive analysis of the performance of MIMO FSO systems utilizing the equal gain combining (EGC) diversity technique under various conditions, such as different numbers of transmitter and receiver, turbulence intensities, the effects of non-zero boresight pointing errors, and path attenuation. The results show that using MIMO technology with more transmitters and receivers significantly improves the performance of FSO communication compared to other diversity techniques, including single input single output (SISO), and multiple input single output (MISO) systems. Detailed evaluations of the ergodic capacity, outage probability, and average BER performance at high signal-to-noise ratios provide additional insights. Monte-Carlo simulation results demonstrate the accuracy of the proposed approach.
本文基于${bm{kappa }}分布，为里氏非零孔径指向误差随机变量之和开发了一种创新的序列表示方法。- {bm{mu }}$ 分布，首次适用于多输入多输出（MIMO）传输。然后，利用这种新表示法，我们为具有广义指向误差和大气衰减的 MIMO 自由空间光学（FSO）通信的 Gamma-Gamma 随机变量之和引入了一种新的闭式概率密度函数（PDF）近似。Kolmogorov-Smirnov 统计测试证实了该近似值在各种信道条件下的准确性。通过使用 Meijer 的 G 函数推导出宏容量、中断概率和平均误码率 (BER) 的闭式表达式，强调了这一近似值的重要性。本文全面分析了利用等增益组合（EGC）分集技术的 MIMO FSO 系统在各种条件下的性能，如不同的发射器和接收器数量、湍流强度、非零孔径指向误差的影响以及路径衰减。研究结果表明，与其他分集技术（包括单输入单输出（SISO）和多输入多输出（MISO）系统）相比，使用具有更多发射器和接收器的多输入多输出（MIMO）技术可显著提高 FSO 通信的性能。对高信噪比情况下的遍历容量、中断概率和平均误码率性能的详细评估提供了更多启示。蒙特卡洛模拟结果证明了所提方法的准确性。
{"title":"Novel Approximate Distribution of the Generalized Turbulence Channels for MIMO FSO Communications","authors":"Wafaa M. R. Shakir;Ali S. Mahdi;Hani Hamdan;Jinan Charafeddine;Haitham Al Satai;Radouane Akrache;Samir Haddad;Jinane Sayah","doi":"10.1109/JPHOT.2024.3418371","DOIUrl":"https://doi.org/10.1109/JPHOT.2024.3418371","url":null,"abstract":"In this article, we develop an innovative series representation for the sum of Rician non-zero boresight pointing error random variates based on the \u0000<inline-formula><tex-math>${bm{kappa }} - {bm{mu }}$</tex-math></inline-formula>\u0000distribution, which is suitable for multiple-input multiple-output (MIMO) transmission for the first time. Then, using this new representation, we introduce a novel closed-form probability density function (PDF) approximation for the sum of Gamma-Gamma random variates with generalized pointing errors and atmospheric attenuation of MIMO free-space optical (FSO) communications. Statistical Kolmogorov-Smirnov tests confirm the accuracy of this approximation over a wide range of channel conditions. The significance of this approximation is emphasized by deriving closed-form expressions for the ergodic capacity, outage probability, and average bit error rate (BER) using Meijer's G-function. This article provides a comprehensive analysis of the performance of MIMO FSO systems utilizing the equal gain combining (EGC) diversity technique under various conditions, such as different numbers of transmitter and receiver, turbulence intensities, the effects of non-zero boresight pointing errors, and path attenuation. The results show that using MIMO technology with more transmitters and receivers significantly improves the performance of FSO communication compared to other diversity techniques, including single input single output (SISO), and multiple input single output (MISO) systems. Detailed evaluations of the ergodic capacity, outage probability, and average BER performance at high signal-to-noise ratios provide additional insights. Monte-Carlo simulation results demonstrate the accuracy of the proposed approach.","PeriodicalId":13204,"journal":{"name":"IEEE Photonics Journal","volume":"16 4","pages":"1-15"},"PeriodicalIF":2.1,"publicationDate":"2024-06-24","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://ieeexplore.ieee.org/stamp/stamp.jsp?tp=&arnumber=10568928","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141495215","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}
In this paper, the feasibility of employing a fast intensity modulator and a chirped fibre Bragg grating to build a dispersion-tuned mode-locked swept laser (DTML-SS) for OCT at 850 nm is evaluated. Stable mode-locking is achieved by applying 50 ps pulses at 1 GHz to the modulator, obtaining 35 nm tuning range at 10 KHz sweep rate and 1 mm axial range.
{"title":"Dispersion-Tuned Mode-Locked Laser for Swept Source OCT at 850 nm Using a cFBG and the Pulse Modulation Technique","authors":"Rene Riha;Alejandro Martinez Jimenez;Gopika Venugopal;Marie Klufts;Robert Huber;Adrian Podoleanu","doi":"10.1109/JPHOT.2024.3417829","DOIUrl":"https://doi.org/10.1109/JPHOT.2024.3417829","url":null,"abstract":"In this paper, the feasibility of employing a fast intensity modulator and a chirped fibre Bragg grating to build a dispersion-tuned mode-locked swept laser (DTML-SS) for OCT at 850 nm is evaluated. Stable mode-locking is achieved by applying 50 ps pulses at 1 GHz to the modulator, obtaining 35 nm tuning range at 10 KHz sweep rate and 1 mm axial range.","PeriodicalId":13204,"journal":{"name":"IEEE Photonics Journal","volume":"16 4","pages":"1-5"},"PeriodicalIF":2.1,"publicationDate":"2024-06-21","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://ieeexplore.ieee.org/stamp/stamp.jsp?tp=&arnumber=10568460","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141474805","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 : 2024-06-21DOI: 10.1109/JPHOT.2024.3417321
Jieling Yu;Wei Fang;Duo Wu;Silong Wang;Zhitao Luo;Yuwei Wang;Yisu Zhang;Xin Ye
The Moon-based Earth Radiation budget Detector (MERD) is an instrument designed to measure the Earth-reflected Solar Radiation (ERSR) and the Earth thermal radiation from the Moon as part of future mission of China's Chang'e project. The accuracy of its calibration technology directly determines the measurement precision. For traceability to International System of Units (SI) and improve the calibration accuracy in the ERSR wave band, a vacuum shortwave radiance calibration system is built, which consists of an in-situ traceable Electrical Substitution Transfer Radiometer (ESTR) and a Shortwave Calibration Light Source (SWCLS). Where, SWCLS is designed with a electrically variable slit and a 12-hole narrow-band filter wheel to achieve continuous broad-spectrum radiance output and discrete narrow-spectrum band tuning, respectively. Additionally, wide dynamic range output is from the introduction of elliptic land spherical mirrors for bilateral highly efficient focusing structure. This paper presents the mathematical process of shortwave calibration and focuses on the design and analysis of SWCLS based on high stability, radiance and uniformity. Results show that light source stability is 0.05922%/h, radiance uniformity is 99.49% at the calibration distance of 300 mm, the range of output radiant brightness in the spectral range 0.3–2.5 μm is 0.03–1272.20 W/m 2 /sr.
{"title":"Research on the Ground Vacuum Shortwave Calibration of Moon-Based Earth Radiation Budget Detector","authors":"Jieling Yu;Wei Fang;Duo Wu;Silong Wang;Zhitao Luo;Yuwei Wang;Yisu Zhang;Xin Ye","doi":"10.1109/JPHOT.2024.3417321","DOIUrl":"10.1109/JPHOT.2024.3417321","url":null,"abstract":"The Moon-based Earth Radiation budget Detector (MERD) is an instrument designed to measure the Earth-reflected Solar Radiation (ERSR) and the Earth thermal radiation from the Moon as part of future mission of China's Chang'e project. The accuracy of its calibration technology directly determines the measurement precision. For traceability to International System of Units (SI) and improve the calibration accuracy in the ERSR wave band, a vacuum shortwave radiance calibration system is built, which consists of an in-situ traceable Electrical Substitution Transfer Radiometer (ESTR) and a Shortwave Calibration Light Source (SWCLS). Where, SWCLS is designed with a electrically variable slit and a 12-hole narrow-band filter wheel to achieve continuous broad-spectrum radiance output and discrete narrow-spectrum band tuning, respectively. Additionally, wide dynamic range output is from the introduction of elliptic land spherical mirrors for bilateral highly efficient focusing structure. This paper presents the mathematical process of shortwave calibration and focuses on the design and analysis of SWCLS based on high stability, radiance and uniformity. Results show that light source stability is 0.05922%/h, radiance uniformity is 99.49% at the calibration distance of 300 mm, the range of output radiant brightness in the spectral range 0.3–2.5 μm is 0.03–1272.20 W/m\u0000<sup>2</sup>\u0000/sr.","PeriodicalId":13204,"journal":{"name":"IEEE Photonics Journal","volume":"16 5","pages":"1-8"},"PeriodicalIF":2.1,"publicationDate":"2024-06-21","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://ieeexplore.ieee.org/stamp/stamp.jsp?tp=&arnumber=10568321","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141504707","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 : 2024-06-18DOI: 10.1109/JPHOT.2024.3416201
Takumi Ishida;Chedlia Ben Naila;Hiraku Okada;Masaaki Katayama
The integration of intelligent reflecting surfaces (IRS) into free-space optical (FSO) communication systems is considered as a promising and innovative approach to overcoming existing challenges due to the strict line-of-sight (LoS) requirements faced by conventional FSO setups, thereby ensuring more flexible and controllable links and expanding the communication coverage area. Nonetheless, the configuration of IRS-assisted FSO systems remains relatively novel, requiring investigation into optimizing IRS placement to enhance system performance while mitigating interference and obstacles in dynamic environmental conditions. This work aims to evaluate the improvement of the system performance achieved through optimized IRS positioning while accounting for the main degrading factors inherent in FSO systems and IRS design. We present a comprehensive model for a multilink terrestrial IRS-assisted FSO system, taking into consideration key degrading factors such as pointing errors stemming from both transmitter and IRS jitter, IRS dimensions, and turbulence-induced fading. Furthermore, we derive closed-form expressions for the probability density function of channel coefficients, average bit error rate, and outage probability. Our results indicate that optimal IRS placement is in proximity to the transmitter, taking into account all channel impairments. Furthermore, we showed that optimal IRS placement tends to shift towards the receiver side as the IRS jitter increases. Consequently, the analysis presented offers valuable insights for efficiently designing IRS-assisted FSO systems, particularly regarding IRS placement in the presence of pointing errors.
{"title":"Performance Analysis of IRS-Assisted Multi-Link FSO System Under Pointing Errors","authors":"Takumi Ishida;Chedlia Ben Naila;Hiraku Okada;Masaaki Katayama","doi":"10.1109/JPHOT.2024.3416201","DOIUrl":"https://doi.org/10.1109/JPHOT.2024.3416201","url":null,"abstract":"The integration of intelligent reflecting surfaces (IRS) into free-space optical (FSO) communication systems is considered as a promising and innovative approach to overcoming existing challenges due to the strict line-of-sight (LoS) requirements faced by conventional FSO setups, thereby ensuring more flexible and controllable links and expanding the communication coverage area. Nonetheless, the configuration of IRS-assisted FSO systems remains relatively novel, requiring investigation into optimizing IRS placement to enhance system performance while mitigating interference and obstacles in dynamic environmental conditions. This work aims to evaluate the improvement of the system performance achieved through optimized IRS positioning while accounting for the main degrading factors inherent in FSO systems and IRS design. We present a comprehensive model for a multilink terrestrial IRS-assisted FSO system, taking into consideration key degrading factors such as pointing errors stemming from both transmitter and IRS jitter, IRS dimensions, and turbulence-induced fading. Furthermore, we derive closed-form expressions for the probability density function of channel coefficients, average bit error rate, and outage probability. Our results indicate that optimal IRS placement is in proximity to the transmitter, taking into account all channel impairments. Furthermore, we showed that optimal IRS placement tends to shift towards the receiver side as the IRS jitter increases. Consequently, the analysis presented offers valuable insights for efficiently designing IRS-assisted FSO systems, particularly regarding IRS placement in the presence of pointing errors.","PeriodicalId":13204,"journal":{"name":"IEEE Photonics Journal","volume":"16 4","pages":"1-10"},"PeriodicalIF":2.1,"publicationDate":"2024-06-18","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://ieeexplore.ieee.org/stamp/stamp.jsp?tp=&arnumber=10561472","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141453511","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 : 2024-06-18DOI: 10.1109/JPHOT.2024.3415635
Qian Wang;Wenqiang Ma;Li Ping Qian;Xinwei Du;Changyuan Yu;Pooi-Yuen Kam
High-order modulations are currently widely used in optical communications to increase the data rate. However, due to the existence of laser phase noise, the performance of high-order modulated systems will be greatly degraded. Therefore, phase estimation (PE) methods and laser linewidth tolerance analysis are particularly important in practice. In this paper, we first propose a common refined Viterbi-Viterbi carrier phase estimator for multi-ring $M$ -ary amplitude phase-shift keying ( $M$ -APSK) with Wiener phase noise. The design is based on the linear minimum mean square error (LMMSE) criterion to optimize the weight coefficients with respect to the statistics of Wiener phase noise and additive, white, Gaussian noise. For simple implementation, approximate ring-detection-based and average-energy-based LMMSE estimators are further derived for multi-ring modulations. The laser linewidth tolerance in Wiener phase noise is analyzed thoroughly compared to the popular PE methods, e.g., decision-aided maximum likelihood and QPSK partitioning. Numerical results show in detail the receiver sensitivity penalties as a function of the estimation memory length, and verify that the proposed estimators do not suffer from the block length effect and perform much better at high signal-to-noise ratio (SNR). They are suitable for coherent demodulation of a multi-ring signal constellation in high SNR or fast-varying phase noise.
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