Pub Date : 2026-01-28DOI: 10.1109/LPT.2026.3658529
Ang Liu;Tong Xia;He Zhao;Shuyuan Zhu;Chaowu Yan;Pu Wang
High-peak-power femtosecond fiber lasers are ideal for biomedical precision processing, but their performance is often limited by gain narrowing. Here, we report a passive, all-fiber gain-flattening scheme based on an unpumped Yb-doped fiber. By utilizing the reabsorption effect of the unpumped Yb-doped fiber as a spectral shaper within the power amplifier, gain narrowing was effectively suppressed. Based on this scheme, the laser system delivered 23.4 W of average power at a 43.8 MHz repetition rate. The broad spectrum supported compression to 84 fs, yielding $0.53~mu $ J pulse energy and a high peak power of 6.4 MW. To verify its practical utility, this source was applied to ex vivo myocardial tissue ablation. Histological analysis confirmed the athermal ablation mechanism, characterized by exceptionally clean incisions devoid of carbonization, protein denaturation, or other collateral thermal damage. This work provides an effective and practical architecture for high-peak-power femtosecond fiber lasers and demonstrates its significant potential for “cold” processing applications, such as athermal surgery.
{"title":"High-Power GMA Fiber Laser Based on Resistance Gain Narrowing for Damage-Free Tissue Ablation","authors":"Ang Liu;Tong Xia;He Zhao;Shuyuan Zhu;Chaowu Yan;Pu Wang","doi":"10.1109/LPT.2026.3658529","DOIUrl":"https://doi.org/10.1109/LPT.2026.3658529","url":null,"abstract":"High-peak-power femtosecond fiber lasers are ideal for biomedical precision processing, but their performance is often limited by gain narrowing. Here, we report a passive, all-fiber gain-flattening scheme based on an unpumped Yb-doped fiber. By utilizing the reabsorption effect of the unpumped Yb-doped fiber as a spectral shaper within the power amplifier, gain narrowing was effectively suppressed. Based on this scheme, the laser system delivered 23.4 W of average power at a 43.8 MHz repetition rate. The broad spectrum supported compression to 84 fs, yielding <inline-formula> <tex-math>$0.53~mu $ </tex-math></inline-formula>J pulse energy and a high peak power of 6.4 MW. To verify its practical utility, this source was applied to ex vivo myocardial tissue ablation. Histological analysis confirmed the athermal ablation mechanism, characterized by exceptionally clean incisions devoid of carbonization, protein denaturation, or other collateral thermal damage. This work provides an effective and practical architecture for high-peak-power femtosecond fiber lasers and demonstrates its significant potential for “cold” processing applications, such as athermal surgery.","PeriodicalId":13065,"journal":{"name":"IEEE Photonics Technology Letters","volume":"38 9","pages":"575-578"},"PeriodicalIF":2.5,"publicationDate":"2026-01-28","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"146139119","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
This work first establishes an 8-channel four pulse amplitude modulation (PAM-4) intensity modulation direct detection (IM-DD) optoelectronic transceiver system, with cascaded silicon Mach-Zehnder interferometer (MZI) lattice-filter technology, for high-speed and long reach (LR) (over 10 km) transmission scenario of modern data center interconnection (DCI). The compact silicon photonic (SiPh) traveling wave Mach-Zehnder modulators (TW-MZM) and silicon-germanium (SiGe) photodetectors (PD) (bandwidth > 49.5 GHz with a responsivity > 0.8 A/W) are homogeneously integrated with MZI lattice-filter based $8times 1$ multiplexer (MUX) and $1times 8$ demultiplexer (DeMUX), respectively, endowing the system with compact structure and tunable operating wavelengths. Finally, the novel SiPh transceiver system is elaborately integrated and applied into the local area network wavelength division multiplexing (LAN-WDM) LR8 circumstance, transmitting over 10 km standard single mode fiber (SSMF), with broad bandwidth (> 33 GHz), good channel response uniformity, and supports over 100 Gbps per lane for high-speed transmission, featuring proper system bit error rate (BER) performance in compliance with IEEE 802.3 standards.
{"title":"Lattice-Filter-Based LAN-WDM Silicon Photonic Transceiver System for DCI LR8 Application","authors":"Xiaojun Ying;Penghui Xia;Ruiqi Luo;Huaqing Jiang;Heng Chen;Kun Yin;Hui Yu;Dan Lu;Tao Chu;Chen Ji","doi":"10.1109/LPT.2026.3655436","DOIUrl":"https://doi.org/10.1109/LPT.2026.3655436","url":null,"abstract":"This work first establishes an 8-channel four pulse amplitude modulation (PAM-4) intensity modulation direct detection (IM-DD) optoelectronic transceiver system, with cascaded silicon Mach-Zehnder interferometer (MZI) lattice-filter technology, for high-speed and long reach (LR) (over 10 km) transmission scenario of modern data center interconnection (DCI). The compact silicon photonic (SiPh) traveling wave Mach-Zehnder modulators (TW-MZM) and silicon-germanium (SiGe) photodetectors (PD) (bandwidth > 49.5 GHz with a responsivity > 0.8 A/W) are homogeneously integrated with MZI lattice-filter based <inline-formula> <tex-math>$8times 1$ </tex-math></inline-formula>multiplexer (MUX) and <inline-formula> <tex-math>$1times 8$ </tex-math></inline-formula> demultiplexer (DeMUX), respectively, endowing the system with compact structure and tunable operating wavelengths. Finally, the novel SiPh transceiver system is elaborately integrated and applied into the local area network wavelength division multiplexing (LAN-WDM) LR8 circumstance, transmitting over 10 km standard single mode fiber (SSMF), with broad bandwidth (> 33 GHz), good channel response uniformity, and supports over 100 Gbps per lane for high-speed transmission, featuring proper system bit error rate (BER) performance in compliance with IEEE 802.3 standards.","PeriodicalId":13065,"journal":{"name":"IEEE Photonics Technology Letters","volume":"38 8","pages":"535-538"},"PeriodicalIF":2.5,"publicationDate":"2026-01-19","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"146082280","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2026-01-19DOI: 10.1109/LPT.2026.3655588
Marco Moller de Freitas;Xiaofeng Zhu;Md. Ifaz Isti;Joshua Arnold;Ruidong Xue;Jiuyi Zhang;Peng Yao;Timothy Creazzo;Christopher Cullen;Shouyuan Shi;Dennis W. Prather
Thin-film lithium niobate (TFLN) electro-optic modulators have been widely explored at 1550 nm, achieving ultra-low driving voltages, broad bandwidths, and compact footprints. Yet, development at 1064 nm has remained comparatively limited, despite its growing importance for applications that demand high power and cost-effective integration with CMOS-compatible silicon photodetectors such as free-space optics, frequency combs and biophotonics. In this work, we demonstrate a high-efficiency TFLN modulator operating at 1064 nm contributing to fulfilling this gap. The device employs a 1 cm-long interaction region with capacitively loaded traveling-wave electrodes designed to minimize the velocity mismatch between RF and optical modes, achieving an index mismatch as low as 0.05. This careful optimization enables a high frequency half-wave voltage of 1.45 V and a 40 GHz 3-dB bandwidth, representing the best performance reported to date for 1064 nm operation. These results highlight the potential of TFLN modulators to extend beyond traditional telecom wavelengths leveraging lower V$pi $ , high quality lasers and easy integration with Si photodetectors.
{"title":"TFLN MZM Operating at 1-μm Wavelength With Low Vπ and High Bandwidth","authors":"Marco Moller de Freitas;Xiaofeng Zhu;Md. Ifaz Isti;Joshua Arnold;Ruidong Xue;Jiuyi Zhang;Peng Yao;Timothy Creazzo;Christopher Cullen;Shouyuan Shi;Dennis W. Prather","doi":"10.1109/LPT.2026.3655588","DOIUrl":"https://doi.org/10.1109/LPT.2026.3655588","url":null,"abstract":"Thin-film lithium niobate (TFLN) electro-optic modulators have been widely explored at 1550 nm, achieving ultra-low driving voltages, broad bandwidths, and compact footprints. Yet, development at 1064 nm has remained comparatively limited, despite its growing importance for applications that demand high power and cost-effective integration with CMOS-compatible silicon photodetectors such as free-space optics, frequency combs and biophotonics. In this work, we demonstrate a high-efficiency TFLN modulator operating at 1064 nm contributing to fulfilling this gap. The device employs a 1 cm-long interaction region with capacitively loaded traveling-wave electrodes designed to minimize the velocity mismatch between RF and optical modes, achieving an index mismatch as low as 0.05. This careful optimization enables a high frequency half-wave voltage of 1.45 V and a 40 GHz 3-dB bandwidth, representing the best performance reported to date for 1064 nm operation. These results highlight the potential of TFLN modulators to extend beyond traditional telecom wavelengths leveraging lower V<inline-formula> <tex-math>$pi $ </tex-math></inline-formula>, high quality lasers and easy integration with Si photodetectors.","PeriodicalId":13065,"journal":{"name":"IEEE Photonics Technology Letters","volume":"38 8","pages":"555-558"},"PeriodicalIF":2.5,"publicationDate":"2026-01-19","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://ieeexplore.ieee.org/stamp/stamp.jsp?tp=&arnumber=11357954","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"146082279","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2026-01-19DOI: 10.1109/LPT.2026.3655104
Siyu Bai;Zehua Xu;Chengshang Lyu;Yibin Li;Qian Li;H. Y. Fu
We propose and experimentally demonstrate a novel frequency–temporal enhanced recovery (FTER) framework to mitigate quantization distortion in ultra-low-resolution (3-5-bit) asymmetrically clipped optical OFDM (ACO-OFDM) optical wireless communication (OWC) links. The FTER scheme combines frequency-domain feature extraction with a temporal convolutional network (TCN)-based denoiser to effectively recover signals suffering from severe quantization noise. In our 1-m OWC experiment with a 680 nm vertical-cavity surface-emitting laser (VCSEL) transmitter, FTER first extracts a rich set of primary and higher-order spectral features from the quantized received signal and employs a random forest to select the most informative features. These features are then fed into a dilated TCN, which learns to suppress structured quantization artifacts and restore the signal. Experimental results confirm that the proposed method enables reliable 32-QAM and 64-QAM transmissions at baud rates up to 0.625 GBaud and 0.75 GBaud, respectively, achieving bit-error rates (BERs) below the hard-decision forward error correction (HD-FEC) threshold. Specifically, under 4-bit quantization with 64-QAM at 0.75 GBaud, the proposed FTER scheme improves the BER from $mathbf {7}.mathbf {2}mathrm {times }{mathbf {10}}^{-mathbf {3}}$ to $mathbf {3}.mathbf {7}mathrm {times }{mathbf {10}}^{-mathbf {3}}$ . These findings demonstrate the feasibility of deploying compact, low-cost OWC links.
{"title":"Frequency-Temporal Enhanced Recovery for Ultra-Low-Resolution ACO-OFDM OWC Links","authors":"Siyu Bai;Zehua Xu;Chengshang Lyu;Yibin Li;Qian Li;H. Y. Fu","doi":"10.1109/LPT.2026.3655104","DOIUrl":"https://doi.org/10.1109/LPT.2026.3655104","url":null,"abstract":"We propose and experimentally demonstrate a novel frequency–temporal enhanced recovery (FTER) framework to mitigate quantization distortion in ultra-low-resolution (3-5-bit) asymmetrically clipped optical OFDM (ACO-OFDM) optical wireless communication (OWC) links. The FTER scheme combines frequency-domain feature extraction with a temporal convolutional network (TCN)-based denoiser to effectively recover signals suffering from severe quantization noise. In our 1-m OWC experiment with a 680 nm vertical-cavity surface-emitting laser (VCSEL) transmitter, FTER first extracts a rich set of primary and higher-order spectral features from the quantized received signal and employs a random forest to select the most informative features. These features are then fed into a dilated TCN, which learns to suppress structured quantization artifacts and restore the signal. Experimental results confirm that the proposed method enables reliable 32-QAM and 64-QAM transmissions at baud rates up to 0.625 GBaud and 0.75 GBaud, respectively, achieving bit-error rates (BERs) below the hard-decision forward error correction (HD-FEC) threshold. Specifically, under 4-bit quantization with 64-QAM at 0.75 GBaud, the proposed FTER scheme improves the BER from <inline-formula> <tex-math>$mathbf {7}.mathbf {2}mathrm {times }{mathbf {10}}^{-mathbf {3}}$ </tex-math></inline-formula> to <inline-formula> <tex-math>$mathbf {3}.mathbf {7}mathrm {times }{mathbf {10}}^{-mathbf {3}}$ </tex-math></inline-formula>. These findings demonstrate the feasibility of deploying compact, low-cost OWC links.","PeriodicalId":13065,"journal":{"name":"IEEE Photonics Technology Letters","volume":"38 9","pages":"567-570"},"PeriodicalIF":2.5,"publicationDate":"2026-01-19","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"146139115","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
We report a highly efficient, Nd-doped all-fiber laser operating based on the three-level transition at 915 nm. A key feature of the laser is a novel active fiber with cladding-embedded absorbing rods that suppress parasitic amplified spontaneous emission (ASE) at 1060 nm. The laser demonstrates 37% slope efficiency, which is, to the best of our knowledge, the highest reported value among all-fiber lasers with near-diffraction-limited beam quality (M${}^{2} lt 1.2$ ). Strong ASE suppression with a signal-to-ASE ratio exceeding 50 dB was achieved. Further output power and efficiency scaling can be reached by optimization of fiber components used in the laser cavity.
{"title":"Monolithic Single-Mode Nd-Doped Fiber Laser Operated at 915-nm With 37% Slope Efficiency","authors":"Danila Davydov;Svetlana Aleshkina;Vladimir Velmiskin;Alexey Lobanov;Mikhail Yashkov;Denis Lipatov;Dmitry Przhiialkovskii;Oleg Butov;Mikhail Likhachev","doi":"10.1109/LPT.2026.3654345","DOIUrl":"https://doi.org/10.1109/LPT.2026.3654345","url":null,"abstract":"We report a highly efficient, Nd-doped all-fiber laser operating based on the three-level transition at 915 nm. A key feature of the laser is a novel active fiber with cladding-embedded absorbing rods that suppress parasitic amplified spontaneous emission (ASE) at 1060 nm. The laser demonstrates 37% slope efficiency, which is, to the best of our knowledge, the highest reported value among all-fiber lasers with near-diffraction-limited beam quality (M<inline-formula> <tex-math>${}^{2} lt 1.2$ </tex-math></inline-formula>). Strong ASE suppression with a signal-to-ASE ratio exceeding 50 dB was achieved. Further output power and efficiency scaling can be reached by optimization of fiber components used in the laser cavity.","PeriodicalId":13065,"journal":{"name":"IEEE Photonics Technology Letters","volume":"38 8","pages":"543-546"},"PeriodicalIF":2.5,"publicationDate":"2026-01-14","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"146082236","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2026-01-12DOI: 10.1109/LPT.2026.3651605
Yazheng Hao;Shuo Zhang;He Su;Rui Yang
We investigate the linear and nonlinear optical responses of a dielectric metasurface exhibiting electromagnetically induced transparency based on bound states in the continuum (BIC) in the near-infrared region. The metasurface is composed of periodically arranged silicon square ring resonators on the top of the SiO2 substrate, with an embedded silicon coupling stripe within each unit cell to break in-plane structural symmetry and facilitate quasi-BIC excitation. Under normal incidence, the proposed design achieves a maximum figure of merit of $2.39times 10^{4}$ , demonstrating an ultrahigh-$Q$ resonance. Additionally, the metasurface supports efficient third harmonic generation effectively with the maximum conversion efficiency of 6.95%. These results provide a promising platform for the applications in high-$Q$ photonics and advanced nonlinear optical devices.
{"title":"Enhancing Linear and Nonlinear Transparent Responses in Stripe-Coupled Metasurface via BIC","authors":"Yazheng Hao;Shuo Zhang;He Su;Rui Yang","doi":"10.1109/LPT.2026.3651605","DOIUrl":"https://doi.org/10.1109/LPT.2026.3651605","url":null,"abstract":"We investigate the linear and nonlinear optical responses of a dielectric metasurface exhibiting electromagnetically induced transparency based on bound states in the continuum (BIC) in the near-infrared region. The metasurface is composed of periodically arranged silicon square ring resonators on the top of the SiO2 substrate, with an embedded silicon coupling stripe within each unit cell to break in-plane structural symmetry and facilitate quasi-BIC excitation. Under normal incidence, the proposed design achieves a maximum figure of merit of <inline-formula> <tex-math>$2.39times 10^{4}$ </tex-math></inline-formula>, demonstrating an ultrahigh-<inline-formula> <tex-math>$Q$ </tex-math></inline-formula> resonance. Additionally, the metasurface supports efficient third harmonic generation effectively with the maximum conversion efficiency of 6.95%. These results provide a promising platform for the applications in high-<inline-formula> <tex-math>$Q$ </tex-math></inline-formula> photonics and advanced nonlinear optical devices.","PeriodicalId":13065,"journal":{"name":"IEEE Photonics Technology Letters","volume":"38 7","pages":"499-502"},"PeriodicalIF":2.5,"publicationDate":"2026-01-12","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"146026634","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2026-01-12DOI: 10.1109/LPT.2026.3653008
Xiao Zhang;Xiaolong Fu;Shuna Yang;Bo Yang;Yiran Gao;Hao Chi
This Letter proposes a novel photonic approach for simultaneous angle-of-arrival (AOA) and frequency measurement based on time stretch. The system employs a dual-polarization single-sideband modulation structure implemented via a DP-BPSK modulator to effectively suppress dispersion-induced fading and enable orthogonal polarization multiplexing. A programmable optical filter is used to ensure spectral uniformity and prevent temporal overlap. After polarization beam splitting and photodetection, stretched waveforms are digitized using low-speed ADCs to extract both AOA and frequency. Experiments for simultaneous measurement of frequency and AOA are demonstrated, within a frequency range of 3–30 GHz and an AOA range of ±70.8°, confirming the system’s capability for wideband RF sensing with relaxed electronic bandwidth requirements.
{"title":"Simultaneous Frequency and AOA Detection via Dual-Polarization Photonic Time Stretch","authors":"Xiao Zhang;Xiaolong Fu;Shuna Yang;Bo Yang;Yiran Gao;Hao Chi","doi":"10.1109/LPT.2026.3653008","DOIUrl":"https://doi.org/10.1109/LPT.2026.3653008","url":null,"abstract":"This Letter proposes a novel photonic approach for simultaneous angle-of-arrival (AOA) and frequency measurement based on time stretch. The system employs a dual-polarization single-sideband modulation structure implemented via a DP-BPSK modulator to effectively suppress dispersion-induced fading and enable orthogonal polarization multiplexing. A programmable optical filter is used to ensure spectral uniformity and prevent temporal overlap. After polarization beam splitting and photodetection, stretched waveforms are digitized using low-speed ADCs to extract both AOA and frequency. Experiments for simultaneous measurement of frequency and AOA are demonstrated, within a frequency range of 3–30 GHz and an AOA range of ±70.8°, confirming the system’s capability for wideband RF sensing with relaxed electronic bandwidth requirements.","PeriodicalId":13065,"journal":{"name":"IEEE Photonics Technology Letters","volume":"38 8","pages":"527-530"},"PeriodicalIF":2.5,"publicationDate":"2026-01-12","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"146082235","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
This letter proposes a dual-track encryption scheme for ciphertext and key based on dynamic window perturbation, enabling highly secure information transmission in both the key and ciphertext dimensions. For key encryption, a modular exponentiation iteration algorithm is used to process the chaotic initial value key, which not only reduces the risk of key leakage but also expands the key space to $10^{99}$ . For ciphertext encryption, a three-dimensional Lorenz chaotic map is used to generate decision factors. Symbols are grouped according to dynamic window sizes, and each group is perturbed and encrypted based on the decision factors. The core advantage of the scheme lies in its symbol-level dynamic grouping encryption mechanism. Unlike traditional bit-level encryption, this scheme avoids the overhead of encrypting each symbol individually by applying dynamic window perturbation to symbol groups, reducing time costs by approximately 50% and more than doubling efficiency. In the 2 kilometer seven-core fiber experiment, the scheme achieved an encrypted signal transmission rate of 110.74 Gb/s, with all fiber cores meeting the hard-decision forward error correction (FEC) bit error rate (BER) threshold of $3.8{,}times{,}10^{-3}$ . Experimental results demonstrate that even in cases of partial key leakage or key misalignment at an unauthorized receiver, the collaboration between the $10^{99}$ key space and the dynamic window perturbation mechanism ensures both the security and processing efficiency of the communication system.
{"title":"Dual-Track Encryption Scheme for Ciphertext and Key Based on Dynamic Window Perturbation","authors":"Zhi Liu;Bo Liu;Jianxin Ren;Yaya Mao;Jianye Zhao;Xiumin Song;Shuaidong Chen;Tingting Sun;Haojun Liu;Chen Wang;Tao Chen","doi":"10.1109/LPT.2026.3653029","DOIUrl":"https://doi.org/10.1109/LPT.2026.3653029","url":null,"abstract":"This letter proposes a dual-track encryption scheme for ciphertext and key based on dynamic window perturbation, enabling highly secure information transmission in both the key and ciphertext dimensions. For key encryption, a modular exponentiation iteration algorithm is used to process the chaotic initial value key, which not only reduces the risk of key leakage but also expands the key space to <inline-formula> <tex-math>$10^{99}$ </tex-math></inline-formula>. For ciphertext encryption, a three-dimensional Lorenz chaotic map is used to generate decision factors. Symbols are grouped according to dynamic window sizes, and each group is perturbed and encrypted based on the decision factors. The core advantage of the scheme lies in its symbol-level dynamic grouping encryption mechanism. Unlike traditional bit-level encryption, this scheme avoids the overhead of encrypting each symbol individually by applying dynamic window perturbation to symbol groups, reducing time costs by approximately 50% and more than doubling efficiency. In the 2 kilometer seven-core fiber experiment, the scheme achieved an encrypted signal transmission rate of 110.74 Gb/s, with all fiber cores meeting the hard-decision forward error correction (FEC) bit error rate (BER) threshold of <inline-formula> <tex-math>$3.8{,}times{,}10^{-3}$ </tex-math></inline-formula>. Experimental results demonstrate that even in cases of partial key leakage or key misalignment at an unauthorized receiver, the collaboration between the <inline-formula> <tex-math>$10^{99}$ </tex-math></inline-formula> key space and the dynamic window perturbation mechanism ensures both the security and processing efficiency of the communication system.","PeriodicalId":13065,"journal":{"name":"IEEE Photonics Technology Letters","volume":"38 8","pages":"551-554"},"PeriodicalIF":2.5,"publicationDate":"2026-01-12","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"146082278","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2026-01-12DOI: 10.1109/LPT.2026.3653052
Chunyu Deng;Zheng Wu;Wanghua Zhu;Kun Yu
The optical power splitter is one of the crucial components of photonics integrated circuits. In this letter, we propose and demonstrate a broadband, compact and polarization-insensitive Y-junction power splitter based on the lithium niobate-on-insulator (LNOI) platform. This device employs an adiabatic coupling structure to achieve a 1:1 power distribution for both TE polarization and TM polarization. Experimental results show that in the wavelength of 1506-1615 nm, the insertion loss of this device is less than 0.7 dB and 0.5 dB for the TE${}_{mathbf {0}}$ and TM${}_{mathbf {0}}$ modes, respectively. Meanwhile, the polarization dependence loss is less than ±0.5dB. The proposed device can be applied to future high-density photonic integrated links.
{"title":"Polarization-Insensitive Y-Junction Power Splitter on Lithium Niobate-on-Insulator Platform","authors":"Chunyu Deng;Zheng Wu;Wanghua Zhu;Kun Yu","doi":"10.1109/LPT.2026.3653052","DOIUrl":"https://doi.org/10.1109/LPT.2026.3653052","url":null,"abstract":"The optical power splitter is one of the crucial components of photonics integrated circuits. In this letter, we propose and demonstrate a broadband, compact and polarization-insensitive Y-junction power splitter based on the lithium niobate-on-insulator (LNOI) platform. This device employs an adiabatic coupling structure to achieve a 1:1 power distribution for both TE polarization and TM polarization. Experimental results show that in the wavelength of 1506-1615 nm, the insertion loss of this device is less than 0.7 dB and 0.5 dB for the TE<inline-formula> <tex-math>${}_{mathbf {0}}$ </tex-math></inline-formula> and TM<inline-formula> <tex-math>${}_{mathbf {0}}$ </tex-math></inline-formula> modes, respectively. Meanwhile, the polarization dependence loss is less than ±0.5dB. The proposed device can be applied to future high-density photonic integrated links.","PeriodicalId":13065,"journal":{"name":"IEEE Photonics Technology Letters","volume":"38 8","pages":"519-522"},"PeriodicalIF":2.5,"publicationDate":"2026-01-12","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"146082282","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2026-01-12DOI: 10.1109/LPT.2026.3652043
Erfan Seifi;Peter LoPresti
This work presents a reinforcement learning (RL) approach for optimizing beam intensity in free-space optical communication (FSOC) links under thermal turbulence. A Twin Delayed Deep Deterministic Policy Gradient (TD3) agent controls Zernike phase parameters on a high-resolution spatial light modulator (SLM) to maximize received power. Experiments at 72°F, 240°F, and 280°F demonstrate consistent convergence and robust performance across varying turbulence levels, with convergence achieved in under 2.7 minutes and average power gains of 2–2.7 dB relative to a flat phase. The method is designed for next-generation low Earth orbit (LEO) optical links, where it can be applied to compact ground station terminals or feeder links to provide real-time adaptive phase correction and maintain stable communication under dynamic channel conditions.
{"title":"Beam Power Optimization in FSO Links Using Reinforcement Learning and SLM Control","authors":"Erfan Seifi;Peter LoPresti","doi":"10.1109/LPT.2026.3652043","DOIUrl":"https://doi.org/10.1109/LPT.2026.3652043","url":null,"abstract":"This work presents a reinforcement learning (RL) approach for optimizing beam intensity in free-space optical communication (FSOC) links under thermal turbulence. A Twin Delayed Deep Deterministic Policy Gradient (TD3) agent controls Zernike phase parameters on a high-resolution spatial light modulator (SLM) to maximize received power. Experiments at 72°F, 240°F, and 280°F demonstrate consistent convergence and robust performance across varying turbulence levels, with convergence achieved in under 2.7 minutes and average power gains of 2–2.7 dB relative to a flat phase. The method is designed for next-generation low Earth orbit (LEO) optical links, where it can be applied to compact ground station terminals or feeder links to provide real-time adaptive phase correction and maintain stable communication under dynamic channel conditions.","PeriodicalId":13065,"journal":{"name":"IEEE Photonics Technology Letters","volume":"38 7","pages":"491-494"},"PeriodicalIF":2.5,"publicationDate":"2026-01-12","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"146026633","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":3,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
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