Pub Date : 2026-06-01Epub Date: 2026-01-12DOI: 10.1016/j.optcom.2026.132906
Xuan Chen, Minghua Cao, Yue Zhang, Huiqin Wang
Optical filter-bank multicarrier with index modulation (OFBMC-IM) suffers from reduced spectral efficiency due to inactive subcarriers. To address this issue, we propose a dual-mode scheme for OFBMC-IM system (DM-OFBMC-IM), which assigns distinct constellation modes to all subcarriers, thereby achieving full carrier utilization while preserving the diversity gain of index modulation. To further enhance bit error rate (BER) performance, phase rotation and amplitude scaling are introduced to adjust both the angular and radial positions of constellation points, generating IM-preferable constellations. Additionally, a deep learning-aided detector, named DMOFIMNet, is developed to recover index and symbol information under channel turbulence, and its hyperparameters are optimized using the Artificial Lemming Algorithm (ALA), thereby maximizing the achievable performance. Simulation and experimental results demonstrate that the proposed DM-OFBMC-IM system not only achieves higher spectral efficiency than benchmark systems but also improves BER performance. In addition, compared to the classical maximum-likelihood detector, the proposed detector reduces computational complexity by approximately 25% while achieving near-optimal BER performance.
{"title":"Deep learning-aided dual-mode index modulation FBMC for optical wireless communications","authors":"Xuan Chen, Minghua Cao, Yue Zhang, Huiqin Wang","doi":"10.1016/j.optcom.2026.132906","DOIUrl":"10.1016/j.optcom.2026.132906","url":null,"abstract":"<div><div>Optical filter-bank multicarrier with index modulation (OFBMC-IM) suffers from reduced spectral efficiency due to inactive subcarriers. To address this issue, we propose a dual-mode scheme for OFBMC-IM system (DM-OFBMC-IM), which assigns distinct constellation modes to all subcarriers, thereby achieving full carrier utilization while preserving the diversity gain of index modulation. To further enhance bit error rate (BER) performance, phase rotation and amplitude scaling are introduced to adjust both the angular and radial positions of constellation points, generating IM-preferable constellations. Additionally, a deep learning-aided detector, named DMOFIMNet, is developed to recover index and symbol information under channel turbulence, and its hyperparameters are optimized using the Artificial Lemming Algorithm (ALA), thereby maximizing the achievable performance. Simulation and experimental results demonstrate that the proposed DM-OFBMC-IM system not only achieves higher spectral efficiency than benchmark systems but also improves BER performance. In addition, compared to the classical maximum-likelihood detector, the proposed detector reduces computational complexity by approximately 25% while achieving near-optimal BER performance.</div></div>","PeriodicalId":19586,"journal":{"name":"Optics Communications","volume":"606 ","pages":"Article 132906"},"PeriodicalIF":2.5,"publicationDate":"2026-06-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145981666","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2026-06-01Epub Date: 2026-01-12DOI: 10.1016/j.optcom.2026.132909
Pankaj Rakheja
The proposed quantum-based image encryption framework introduces an asymmetric mechanism for standard grayscale and iris biometric images by integrating quantum theory, unequal modulus decomposition, umbrella mapping, LU decomposition, fractional Fourier and Fresnel transforms. Biometric uniqueness is explicitly embedded within cryptographic operations; the scheme achieves high robustness and security while ensuring confidentiality and authentication. The numerical simulations demonstrate the superior performance of the proposed scheme, achieving average execution time of seconds, entropy of bits, and strong statistical metrics, including and confirming robust encryption and perfect image reconstruction fidelity. The system shows strong resistance to noise, brute force, special, differential, and traditional cryptographic attacks, supported by an extended key space. Despite generating a complex cipher and being vulnerable to occlusion attack, the designed scheme ensures reliability, scalability, and security. This makes the scheme suitable for real-life applications in multiple domains like healthcare, defense, and multimedia communication, with potential enhancements through hardware implementations.
{"title":"Robust quantum optical encryption framework using chaotic umbrella maps and fractional transforms with holographic techniques","authors":"Pankaj Rakheja","doi":"10.1016/j.optcom.2026.132909","DOIUrl":"10.1016/j.optcom.2026.132909","url":null,"abstract":"<div><div>The proposed quantum-based image encryption framework introduces an asymmetric mechanism for standard grayscale and iris biometric images by integrating quantum theory, unequal modulus decomposition, umbrella mapping, LU decomposition, fractional Fourier and Fresnel transforms. Biometric uniqueness is explicitly embedded within cryptographic operations; the scheme achieves high robustness and security while ensuring confidentiality and authentication. The numerical simulations demonstrate the superior performance of the proposed scheme, achieving average execution time of <span><math><mrow><mn>0.1132</mn></mrow></math></span> seconds, entropy of <span><math><mrow><mn>7.9955</mn></mrow></math></span> bits, and strong statistical metrics, including <span><math><mrow><mi>N</mi><mi>P</mi><mi>C</mi><mi>R</mi><mo>=</mo><mn>99.6063</mn><mo>,</mo><mi>U</mi><mi>A</mi><mi>C</mi><mi>I</mi><mo>=</mo><mn>33.3283</mn><mo>,</mo><mi>C</mi><mi>C</mi><mo>=</mo><mn>1</mn><mtext>,</mtext></mrow></math></span> and <span><math><mrow><mi>M</mi><mi>S</mi><mi>E</mi><mo>=</mo><mn>0</mn><mtext>,</mtext></mrow></math></span> confirming robust encryption and perfect image reconstruction fidelity. The system shows strong resistance to noise, brute force, special, differential, and traditional cryptographic attacks, supported by an extended key space. Despite generating a complex cipher and being vulnerable to occlusion attack, the designed scheme ensures reliability, scalability, and security. This makes the scheme suitable for real-life applications in multiple domains like healthcare, defense, and multimedia communication, with potential enhancements through hardware implementations.</div></div>","PeriodicalId":19586,"journal":{"name":"Optics Communications","volume":"606 ","pages":"Article 132909"},"PeriodicalIF":2.5,"publicationDate":"2026-06-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"146039186","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2026-06-01Epub Date: 2026-01-13DOI: 10.1016/j.optcom.2026.132893
Andrew MacRae , Connor Kupchak
We study the limitations on observing transient amplification in atomic systems exhibiting electromagnetically induced transparency (EIT) and we evaluate the limits of optical Bloch equation (OBE) models. Using propagation-based Maxwell–Bloch simulations, we show that single-atom, spatially uniform OBE treatments overestimate gain by neglecting propagation dynamics. In two-level systems, this yields incorrect predictions of the transmission, while in three-level systems, it predicts unrealistically large amplification. Furthermore, we show that Doppler averaging in warm vapor suppresses oscillatory ringing and the maximum achievable gain. Our results explain discrepancies between OBE predictions and experimental observations, and establish practical limits on transient gain in cold and thermally broadened EIT media.
{"title":"Propagation dynamics and transient amplification in warm and cold atomic EIT systems","authors":"Andrew MacRae , Connor Kupchak","doi":"10.1016/j.optcom.2026.132893","DOIUrl":"10.1016/j.optcom.2026.132893","url":null,"abstract":"<div><div>We study the limitations on observing transient amplification in atomic systems exhibiting electromagnetically induced transparency (EIT) and we evaluate the limits of optical Bloch equation (OBE) models. Using propagation-based Maxwell–Bloch simulations, we show that single-atom, spatially uniform OBE treatments overestimate gain by neglecting propagation dynamics. In two-level systems, this yields incorrect predictions of the transmission, while in three-level systems, it predicts unrealistically large amplification. Furthermore, we show that Doppler averaging in warm vapor suppresses oscillatory ringing and the maximum achievable gain. Our results explain discrepancies between OBE predictions and experimental observations, and establish practical limits on transient gain in cold and thermally broadened EIT media.</div></div>","PeriodicalId":19586,"journal":{"name":"Optics Communications","volume":"606 ","pages":"Article 132893"},"PeriodicalIF":2.5,"publicationDate":"2026-06-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145980884","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2026-06-01Epub Date: 2025-11-01DOI: 10.1016/j.optcom.2025.132599
Jiarui Zhao , Xihan Wu , Jian Feng , Shaochi Pan , Zhongmin He , Zhenhuan Qiu , Yichun Chen , Xing Zhang , Wei Miao , Bin Wang , Shihao Ding , Shupeng Deng , Nannan Li , Jinlong Lu , Hui Li , Junying Li , Chuyu Zhong
Vertical cavity surface emitting lasers (VCSEL) offer advantages such as low threshold, high modulation speed, and circular beam profiles etc., making them well suited for applications in optical communication and sensing. However, their intrinsic beam divergence limits free-space performance, and conventional beam-shaping optics are not easily integrated. Integrating micro-optical elements directly on the VCSEL facet has thus emerged as an effective approach for on-chip beam control, with commonly used micro-structures including microlens, diffractive optical elements (DOE), metalens and so on. Among various approaches, metalens enable flexible and multifunctional wavefront manipulation, including focusing, collimation, and polarization control. In this work, we design a reconfigurable metalens based on the low-loss phase-change material Sb2Se3, achieving a continuously tunable focal length from 35 μm to 55 μm, with focusing efficiencies exceeding 54 %. The metalens is further integrated onto the p-side distributed Bragg reflector (p-DBR) of a 1550 nm VCSEL. We investigate the optical compatibility of this monolithic integration scheme by analyzing the influence of the metalens on the spectrum, longitudinal and transverse modes, and far-field divergence of VCSEL. Results show that integration exerts minimal influence on cavity mode stability and confirms the spectral compatibility. This integration approach offers a promising route toward compact and tunable VCSEL based photonic systems.
{"title":"Reconfigurable beam steering of multimode VCSEL using multifocal metalens based on phase-change material","authors":"Jiarui Zhao , Xihan Wu , Jian Feng , Shaochi Pan , Zhongmin He , Zhenhuan Qiu , Yichun Chen , Xing Zhang , Wei Miao , Bin Wang , Shihao Ding , Shupeng Deng , Nannan Li , Jinlong Lu , Hui Li , Junying Li , Chuyu Zhong","doi":"10.1016/j.optcom.2025.132599","DOIUrl":"10.1016/j.optcom.2025.132599","url":null,"abstract":"<div><div>Vertical cavity surface emitting lasers (VCSEL) offer advantages such as low threshold, high modulation speed, and circular beam profiles etc., making them well suited for applications in optical communication and sensing. However, their intrinsic beam divergence limits free-space performance, and conventional beam-shaping optics are not easily integrated. Integrating micro-optical elements directly on the VCSEL facet has thus emerged as an effective approach for on-chip beam control, with commonly used micro-structures including microlens, diffractive optical elements (DOE), metalens and so on. Among various approaches, metalens enable flexible and multifunctional wavefront manipulation, including focusing, collimation, and polarization control. In this work, we design a reconfigurable metalens based on the low-loss phase-change material Sb<sub>2</sub>Se<sub>3</sub>, achieving a continuously tunable focal length from 35 μm to 55 μm, with focusing efficiencies exceeding 54 %. The metalens is further integrated onto the p-side distributed Bragg reflector (p-DBR) of a 1550 nm VCSEL. We investigate the optical compatibility of this monolithic integration scheme by analyzing the influence of the metalens on the spectrum, longitudinal and transverse modes, and far-field divergence of VCSEL. Results show that integration exerts minimal influence on cavity mode stability and confirms the spectral compatibility. This integration approach offers a promising route toward compact and tunable VCSEL based photonic systems.</div></div>","PeriodicalId":19586,"journal":{"name":"Optics Communications","volume":"606 ","pages":"Article 132599"},"PeriodicalIF":2.5,"publicationDate":"2026-06-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"146078915","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2026-06-01Epub Date: 2026-01-16DOI: 10.1016/j.optcom.2026.132921
Shubin Hua , Ning Zhang , Yina Hai , Deqiang Ding , Peng Yin , Zhaolong He , Fangyu Sun , Huidong Guo , Wenda Shao
To enhance the concentration efficiency and space utilization of the concentrator, a stepped integrated photovoltaic concentrating system without Light Leakage has been developed. The interrelationships between the geometric concentration ratio, parabolic coefficient, light guide plate (LGP) step height, and the height of the outermost concentrating module have been thoroughly investigated. To address the issue of light leakage caused by the low acceptance angle after light coupling into the LGP, a design method for a stepped leak-proof light guide plate has been proposed. Considering the solar divergence angle, Fresnel losses, and material absorption, LightTools optical simulation software was used to trace the light rays of the designed system, revealing the impact of the LGP step height, the height of the outermost concentrating module, and the acceptance half-angle on the system's optical efficiency. The simulation results show that, when the step height is 0.1 cm, the geometric concentration ratio reaches 306, with a concentration efficiency of 64.70 %. When the step height increases to 0.5 cm, the geometric concentration ratio decreases to 62, while the concentration efficiency increases to 83.62 %. Additionally, as the axial error increases from 0° to 0.3°, the average energy flux density decreases from 7011.37 W/m2 to 6320.74 W/m2, with the concentrator efficiency reaching approximately 90.14 % of the peak value. In contrast, as the alignment error increases from 0° to 0.3°, the average energy flux density decreases from 7011.37 W/m2 to 6674.62 W/m2, and the concentrator efficiency reaches approximately 95.1 % of the peak value. Experimental results indicate that the designed concentrator achieves a peak concentration efficiency of 55.8 % at noon.
{"title":"The design method of stepped integrated photovoltaic concentrator without light leakage","authors":"Shubin Hua , Ning Zhang , Yina Hai , Deqiang Ding , Peng Yin , Zhaolong He , Fangyu Sun , Huidong Guo , Wenda Shao","doi":"10.1016/j.optcom.2026.132921","DOIUrl":"10.1016/j.optcom.2026.132921","url":null,"abstract":"<div><div>To enhance the concentration efficiency and space utilization of the concentrator, a stepped integrated photovoltaic concentrating system without Light Leakage has been developed. The interrelationships between the geometric concentration ratio, parabolic coefficient, light guide plate (LGP) step height, and the height of the outermost concentrating module have been thoroughly investigated. To address the issue of light leakage caused by the low acceptance angle after light coupling into the LGP, a design method for a stepped leak-proof light guide plate has been proposed. Considering the solar divergence angle, Fresnel losses, and material absorption, LightTools optical simulation software was used to trace the light rays of the designed system, revealing the impact of the LGP step height, the height of the outermost concentrating module, and the acceptance half-angle on the system's optical efficiency. The simulation results show that, when the step height is 0.1 cm, the geometric concentration ratio reaches 306, with a concentration efficiency of 64.70 %. When the step height increases to 0.5 cm, the geometric concentration ratio decreases to 62, while the concentration efficiency increases to 83.62 %. Additionally, as the axial error increases from 0° to 0.3°, the average energy flux density decreases from 7011.37 W/m<sup>2</sup> to 6320.74 W/m<sup>2</sup>, with the concentrator efficiency reaching approximately 90.14 % of the peak value. In contrast, as the alignment error increases from 0° to 0.3°, the average energy flux density decreases from 7011.37 W/m<sup>2</sup> to 6674.62 W/m<sup>2</sup>, and the concentrator efficiency reaches approximately 95.1 % of the peak value. Experimental results indicate that the designed concentrator achieves a peak concentration efficiency of 55.8 % at noon.</div></div>","PeriodicalId":19586,"journal":{"name":"Optics Communications","volume":"607 ","pages":"Article 132921"},"PeriodicalIF":2.5,"publicationDate":"2026-06-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"146025931","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2026-06-01Epub Date: 2026-01-27DOI: 10.1016/j.optcom.2025.132779
Xiang Sui , Ying Shang , Sheng Huang , Wenan Zhao , Xiaohan Qiao , Guangqiang Liu , Chunmei Yao , Shouling Liu , Na Wan , Xianggui Kong , Hong Zhao , Fengming Mou , Zhengying Li , Weitao Wang , Chen Wang , Gangding Peng
{"title":"Corrigendum to “Coherent fading suppression method in the COTDR system based on multi-band filtering” [Opt. Commun. 583 (2025) 131696]","authors":"Xiang Sui , Ying Shang , Sheng Huang , Wenan Zhao , Xiaohan Qiao , Guangqiang Liu , Chunmei Yao , Shouling Liu , Na Wan , Xianggui Kong , Hong Zhao , Fengming Mou , Zhengying Li , Weitao Wang , Chen Wang , Gangding Peng","doi":"10.1016/j.optcom.2025.132779","DOIUrl":"10.1016/j.optcom.2025.132779","url":null,"abstract":"","PeriodicalId":19586,"journal":{"name":"Optics Communications","volume":"607 ","pages":"Article 132779"},"PeriodicalIF":2.5,"publicationDate":"2026-06-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"146080153","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2026-06-01Epub Date: 2026-01-03DOI: 10.1016/j.optcom.2025.132837
Xi Fang, YunZhang Wang, Shun Lv, LingYu Liu, SiLu Fan, LingXiao Liu
In high-speed WDM PDM CO-OFDM systems, nonlinear distortion and frequency-domain coupling severely impact in-phase/quadrature (IQ) recovery in coherent optical receivers. We propose LTNE, a lightweight Transformer-based equalizer specifically tailored for frequency-domain IQ signal recovery. Unlike generic local-attention approaches, LTNE employs a sliding-window design motivated by the localized nature of fiber-induced nonlinear inter-subcarrier coupling. By predicting the center subcarrier within each local spectral window, LTNE captures the most relevant high-order nonlinear interactions while avoiding unnecessary global attention. This approach effectively reduces computational complexity while preserving phase continuity essential for coherent detection. Under 50 GHz spacing, 500 km reach, and 500 kHz linewidth conditions, LTNE maintains BER below 3.8 × 10−3 and remains robust for 64/128-QAM formats where conventional methods fail. With 10 × faster inference and 55.6 % fewer parameters than standard Transformers, LTNE demonstrates both high-order robustness and practical feasibility for real-time optical IQ recovery.
{"title":"Lightweight Transformer-based nonlinear equalization for robust IQ recovery in WDM PDM CO-OFDM systems","authors":"Xi Fang, YunZhang Wang, Shun Lv, LingYu Liu, SiLu Fan, LingXiao Liu","doi":"10.1016/j.optcom.2025.132837","DOIUrl":"10.1016/j.optcom.2025.132837","url":null,"abstract":"<div><div>In high-speed WDM PDM CO-OFDM systems, nonlinear distortion and frequency-domain coupling severely impact in-phase/quadrature (IQ) recovery in coherent optical receivers. We propose LTNE, a lightweight Transformer-based equalizer specifically tailored for frequency-domain IQ signal recovery. Unlike generic local-attention approaches, LTNE employs a sliding-window design motivated by the localized nature of fiber-induced nonlinear inter-subcarrier coupling. By predicting the center subcarrier within each local spectral window, LTNE captures the most relevant high-order nonlinear interactions while avoiding unnecessary global attention. This approach effectively reduces computational complexity while preserving phase continuity essential for coherent detection. Under 50 GHz spacing, 500 km reach, and 500 kHz linewidth conditions, LTNE maintains BER below 3.8 × 10<sup>−3</sup> and remains robust for 64/128-QAM formats where conventional methods fail. With 10 × faster inference and 55.6 % fewer parameters than standard Transformers, LTNE demonstrates both high-order robustness and practical feasibility for real-time optical IQ recovery.</div></div>","PeriodicalId":19586,"journal":{"name":"Optics Communications","volume":"607 ","pages":"Article 132837"},"PeriodicalIF":2.5,"publicationDate":"2026-06-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"146026025","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2026-06-01Epub Date: 2026-01-24DOI: 10.1016/j.optcom.2026.132960
Gaurav Verma , Wenqi He
The Optical Phase Retrieval (OPR) technique represents an innovative encoding approach that enforces constraints in both the Fourier and spatial domains to generate a phase-only representation of data. Discarding amplitude information inherently achieves data compression in the Fourier domain while preserving essential structural details. This paper presents an efficient and secure video encryption framework integrating OPR with multimodal chaotic-map modulation for enhanced robustness and confidentiality. In the proposed method, video sequences are decomposed into individual frames, which are encoded into phase-only distributions using an iterative OPR algorithm. These encoded frames are further encrypted through multimodal chaotic maps, including Logistic and Henon systems, ensuring high key sensitivity, strong diffusion, and nonlinear randomness. The integrated framework achieves efficient data compression, secure transmission, and robustness against perturbations. The numerical results demonstrate that the proposed scheme achieves a large key space and strong sensitivity, and offers efficient computation time complexity, also effectively showing reliable performance against video processing attacks such as compression, rotation, and blurring. Comprehensive experiments under diverse degradations — such as Gaussian noise, salt-and-pepper noise, and partial occlusion — demonstrate that the proposed system provides high-quality reconstruction during decryption. Statistical evaluations using metrics such as MSE, PSNR, SSIM, and entropy confirm excellent decryption fidelity and strong resistance to standard cryptographic attacks. Furthermore, the proposed system exhibits real-time processing capabilities, making it a suitable choice for next-generation optical video encryption and secure multimedia communication applications.
{"title":"Optical video encryption using iterative phase retrieval and multimodal chaotic maps","authors":"Gaurav Verma , Wenqi He","doi":"10.1016/j.optcom.2026.132960","DOIUrl":"10.1016/j.optcom.2026.132960","url":null,"abstract":"<div><div>The Optical Phase Retrieval (OPR) technique represents an innovative encoding approach that enforces constraints in both the Fourier and spatial domains to generate a phase-only representation of data. Discarding amplitude information inherently achieves data compression in the Fourier domain while preserving essential structural details. This paper presents an efficient and secure video encryption framework integrating OPR with multimodal chaotic-map modulation for enhanced robustness and confidentiality. In the proposed method, video sequences are decomposed into individual frames, which are encoded into phase-only distributions using an iterative OPR algorithm. These encoded frames are further encrypted through multimodal chaotic maps, including Logistic and Henon systems, ensuring high key sensitivity, strong diffusion, and nonlinear randomness. The integrated framework achieves efficient data compression, secure transmission, and robustness against perturbations. The numerical results demonstrate that the proposed scheme achieves a large key space and strong sensitivity, and offers efficient computation time complexity, also effectively showing reliable performance against video processing attacks such as compression, rotation, and blurring. Comprehensive experiments under diverse degradations — such as Gaussian noise, salt-and-pepper noise, and partial occlusion — demonstrate that the proposed system provides high-quality reconstruction during decryption. Statistical evaluations using metrics such as MSE, PSNR, SSIM, and entropy confirm excellent decryption fidelity and strong resistance to standard cryptographic attacks. Furthermore, the proposed system exhibits real-time processing capabilities, making it a suitable choice for next-generation optical video encryption and secure multimedia communication applications.</div></div>","PeriodicalId":19586,"journal":{"name":"Optics Communications","volume":"607 ","pages":"Article 132960"},"PeriodicalIF":2.5,"publicationDate":"2026-06-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"146080063","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2026-06-01Epub Date: 2026-01-21DOI: 10.1016/j.optcom.2026.132925
Xiansheng Li, Jun Xin
Multimode quantum entangled states play a crucial role in quantum information processing. However, the generation of large-scale multimode quantum entanglement in the spatial degree of freedom remains a significant challenge. In this paper, we theoretically propose a scheme for generating spatial multimode entangled states through four-wave mixing processes. Our approach is based on the topology of an SU(1,1) interferometer (SUI). For an input beam with spatial modes exhibiting circular symmetry, we demonstrate that a -mode spatially entangled state can be generated by rotating the spatial modes of the beam in one arm of the SUI along the optical axis.
{"title":"Generating spatial multimode entanglement using a spatial-mode-rotated SU(1,1) interferometer: Theoretical study","authors":"Xiansheng Li, Jun Xin","doi":"10.1016/j.optcom.2026.132925","DOIUrl":"10.1016/j.optcom.2026.132925","url":null,"abstract":"<div><div>Multimode quantum entangled states play a crucial role in quantum information processing. However, the generation of large-scale multimode quantum entanglement in the spatial degree of freedom remains a significant challenge. In this paper, we theoretically propose a scheme for generating spatial multimode entangled states through four-wave mixing processes. Our approach is based on the topology of an SU(1,1) interferometer (SUI). For an input beam with <span><math><mi>n</mi></math></span> spatial modes exhibiting circular symmetry, we demonstrate that a <span><math><mrow><mn>2</mn><mi>n</mi></mrow></math></span>-mode spatially entangled state can be generated by rotating the spatial modes of the beam in one arm of the SUI along the optical axis.</div></div>","PeriodicalId":19586,"journal":{"name":"Optics Communications","volume":"607 ","pages":"Article 132925"},"PeriodicalIF":2.5,"publicationDate":"2026-06-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"146080129","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"物理与天体物理","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2026-06-01Epub Date: 2026-01-13DOI: 10.1016/j.optcom.2026.132904
Michael G. Taylor
This paper describes the passage of light through a system of waveplates mathematically in terms of quaternions, an extension of the complex numbers, instead of the more usual Jones vectors and Jones matrices. Both the light beam and the waveplate are represented by a quaternion. It is possible to manipulate the quaternion expression more readily than the Jones matrix-vector expression; for example it can be inverted. The quaternion form of a waveplate is compactly related to its retardance and fast/slow axes, and the quaternion of a signal is closely related to its state of polarization (SOP), either expressed as a vector on the Poincaré sphere or as a polarization ellipse. The paper presents rules to decide if two optical signals are aligned or orthogonal in phase or in polarization from their quaternions, and presents the quaternion operations to change the phase or change the SOP. Several mathematical tools are identified, such as partial conjugation, to rearrange a quaternion expression, a tricky operation because multiplication does not commute. Put together, these advances let us understand how waveplates can act on a light beam to produce desired behavior. Finally, the quaternion math is put to work on two problems. A new endless optical phase shift system is designed out of waveplates. A prior solution to the problem used five waveplates, and in this paper the same task is done with only three waveplates. Also, failures of a polarization controller are studied, and found to be caused by singularities, which can occur frequently.
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