Pub Date : 2025-11-17DOI: 10.1109/JLT.2025.3633993
J. J. Navarro-Alventosa;A. Aupart-Acosta;V. Durán
Computational techniques have gained significant traction in photonics, enabling the co-design of hardware and data processing algorithms to drastically simplify optical system architectures and improve their performance. However, their application in optical frequency comb spectroscopy remains considerably underexplored. In this work, we introduce a non-interferometric approach to frequency comb spectroscopy based on dynamically tailored electro-optic modulation. The core of our method is a reconfigurable electro-optic comb generator capable of producing a sequence of known comb spectra to interrogate a spectroscopic sample. Instead of recording spectrally resolved or interferometric data, our system captures a set of integrated optical power measurements—one per probe comb—from which the sample’s spectral response is computationally reconstructed by solving an inverse problem. We present the theoretical foundations of this method, assess its limitations, and validate it through numerical simulations. As a proof of concept, we demonstrate the experimental reconstruction of several spectral signatures, including a molecular absorption line at 1545 nm. For these results, we use numerically computed spectra and experimentally measured power values, all acquired within 10 milliseconds. Finally, we discuss potential extensions and improvements of the method, as well as its integration into chip-scale spectroscopic systems.
{"title":"Computational Electro-Optic Frequency Comb Spectroscopy","authors":"J. J. Navarro-Alventosa;A. Aupart-Acosta;V. Durán","doi":"10.1109/JLT.2025.3633993","DOIUrl":"https://doi.org/10.1109/JLT.2025.3633993","url":null,"abstract":"Computational techniques have gained significant traction in photonics, enabling the co-design of hardware and data processing algorithms to drastically simplify optical system architectures and improve their performance. However, their application in optical frequency comb spectroscopy remains considerably underexplored. In this work, we introduce a non-interferometric approach to frequency comb spectroscopy based on dynamically tailored electro-optic modulation. The core of our method is a reconfigurable electro-optic comb generator capable of producing a sequence of known comb spectra to interrogate a spectroscopic sample. Instead of recording spectrally resolved or interferometric data, our system captures a set of integrated optical power measurements—one per probe comb—from which the sample’s spectral response is computationally reconstructed by solving an inverse problem. We present the theoretical foundations of this method, assess its limitations, and validate it through numerical simulations. As a proof of concept, we demonstrate the experimental reconstruction of several spectral signatures, including a molecular absorption line at 1545 nm. For these results, we use numerically computed spectra and experimentally measured power values, all acquired within 10 milliseconds. Finally, we discuss potential extensions and improvements of the method, as well as its integration into chip-scale spectroscopic systems.","PeriodicalId":16144,"journal":{"name":"Journal of Lightwave Technology","volume":"44 2","pages":"623-633"},"PeriodicalIF":4.8,"publicationDate":"2025-11-17","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145915554","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
A rapid phase demodulation on enhanced frequency channel (RP-EFC) method for long-distance distributed acoustic sensing (DAS) based on single-shot linear frequency modulation (LFM) is proposed. Interference of LFM pulse between random scattering points form frequency channels. Interference-enhanced frequency channels are selected by channel evaluation process for phase demodulation. RP-EFC demonstrates low computational complexity while keeping the capability of immune interference fading. The experiment is carried out with 41 km sensing fiber and shows excellent demodulation performance even for ultra-low signal-noise-ratio 2.79 dB. A 27.03 dB noise suppression at frequency 4 Hz and 0.32 nϵ/√Hz@41 km sensitivity are realized. Compared to traditional time delay estimation demodulation method, the calculate time is decreased by 198 times under 500-points computational window for whole sensing fiber.
{"title":"Rapid Phase Demodulation on Enhanced Frequency Channel for Single-Shot Distributed Acoustic Sensing","authors":"Enbang Zhao;Junfeng Jiang;Shuang Wang;Kun Liu;Mingjiang Zhang;Xiaoshuang Dai;Aichun Liu;Xuezhi Zhang;Yixuan Wang;Zhenyang Ding;Tiegen Liu","doi":"10.1109/JLT.2025.3632824","DOIUrl":"https://doi.org/10.1109/JLT.2025.3632824","url":null,"abstract":"A rapid phase demodulation on enhanced frequency channel (RP-EFC) method for long-distance distributed acoustic sensing (DAS) based on single-shot linear frequency modulation (LFM) is proposed. Interference of LFM pulse between random scattering points form frequency channels. Interference-enhanced frequency channels are selected by channel evaluation process for phase demodulation. RP-EFC demonstrates low computational complexity while keeping the capability of immune interference fading. The experiment is carried out with 41 km sensing fiber and shows excellent demodulation performance even for ultra-low signal-noise-ratio 2.79 dB. A 27.03 dB noise suppression at frequency 4 Hz and 0.32 nϵ/√Hz@41 km sensitivity are realized. Compared to traditional time delay estimation demodulation method, the calculate time is decreased by 198 times under 500-points computational window for whole sensing fiber.","PeriodicalId":16144,"journal":{"name":"Journal of Lightwave Technology","volume":"44 2","pages":"735-742"},"PeriodicalIF":4.8,"publicationDate":"2025-11-13","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145915558","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"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 : 2025-11-12DOI: 10.1109/JLT.2025.3632244
Di Che;Callum Deakin;Xi Chen;Gregory Raybon
The ability to generate high-symbol-rate signals has been instrumental in pushing the speed limits of optical fiber communications. Over the past 50 years, the reported electronic symbol rates at the Optical Fiber Communication Conference (OFC) have improved from 123 MBaud in 1975 to 440 GBaud in 2025. This paper reviews the historical evolution of symbol rates in both laboratory demonstrations and commercial products, with a particular focus on the coherent era. We highlight a crucial technique that has improved symbol rates in laboratories over decades – electronic multiplexing and discuss its role in future coherent systems. Laboratory symbol rates have plateaued around the 200-GBaud level for nearly a decade, and this level is now transitioning into 1.6-Tb/s commercial products. Here, we report a record Nyquist symbol rate of 440 GBaud, doubling the state-of-the-art using a newly designed digital-band-interleaving (DBI) transmitter providing an analog bandwidth of 221 GHz. The signal drives a thin-film Lithium Niobate modulator and exhibits a flat-top spectrum across 440-GHz optical bandwidth without optical equalization. High transmitter quality enables probabilistically shaped 16-level amplitude modulation achieving a net rate over 1 Tb/s per modulation dimension. The 200-GHz class DBI system can support research and development at both component and subsystem levels for next-generation single-channel 400-GBaud client optics targeting 800 Gb/s or coherent optics at 3.2 Tb/s.
{"title":"440-GBaud All-Electronic Signaling Enabling Single-Wavelength Net Rate Over 1 Tb/s Per Modulation Dimension","authors":"Di Che;Callum Deakin;Xi Chen;Gregory Raybon","doi":"10.1109/JLT.2025.3632244","DOIUrl":"https://doi.org/10.1109/JLT.2025.3632244","url":null,"abstract":"The ability to generate high-symbol-rate signals has been instrumental in pushing the speed limits of optical fiber communications. Over the past 50 years, the reported electronic symbol rates at the Optical Fiber Communication Conference (OFC) have improved from 123 MBaud in 1975 to 440 GBaud in 2025. This paper reviews the historical evolution of symbol rates in both laboratory demonstrations and commercial products, with a particular focus on the coherent era. We highlight a crucial technique that has improved symbol rates in laboratories over decades – electronic multiplexing and discuss its role in future coherent systems. Laboratory symbol rates have plateaued around the 200-GBaud level for nearly a decade, and this level is now transitioning into 1.6-Tb/s commercial products. Here, we report a record Nyquist symbol rate of 440 GBaud, doubling the state-of-the-art using a newly designed digital-band-interleaving (DBI) transmitter providing an analog bandwidth of 221 GHz. The signal drives a thin-film Lithium Niobate modulator and exhibits a flat-top spectrum across 440-GHz optical bandwidth without optical equalization. High transmitter quality enables probabilistically shaped 16-level amplitude modulation achieving a net rate over 1 Tb/s per modulation dimension. The 200-GHz class DBI system can support research and development at both component and subsystem levels for next-generation single-channel 400-GBaud client optics targeting 800 Gb/s or coherent optics at 3.2 Tb/s.","PeriodicalId":16144,"journal":{"name":"Journal of Lightwave Technology","volume":"44 3","pages":"1178-1193"},"PeriodicalIF":4.8,"publicationDate":"2025-11-12","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://ieeexplore.ieee.org/stamp/stamp.jsp?tp=&arnumber=11244224","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"146071154","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2025-11-11DOI: 10.1109/JLT.2025.3631875
Cong Liu;Haozhi Wang;Ruofan Wang;Jianguan Tang;Cheng Cheng;Minghong Yang
Distributed acoustic sensing (DAS) in complex engineering environments and large-scale applications demands multiplexing strategies capable of multipath interrogation and wideband frequency response. However, conventional interrogation using single mode fibers has difficulty in satisfying these requirements. This study establishes a high-fidelity numerical model of phase-sensitive optical time domain reflectometry (ϕ-OTDR) that integrates ultra-weak fiber Bragg grating (UWFBG) array with pulse compression and phase noise compensation (PNC) technique. A detailed examination of static and dynamic crosstalk under space-division multiplexing (SDM) and time-division multiplexing (TDM) reveals the significant roles of Rayleigh backscattering and laser phase noise in limiting sensing performance. Experimental validation of PNC efficiency and crosstalk characteristics in both SDM and TDM configurations exhibits strong agreement with theoretical and numerical results. Notably, this model provides a systematic framework for evaluating crosstalk and optimizing overall system performance in DAS applications employing advanced multiplexing techniques.
{"title":"Numerical Modeling of ϕ-OTDR Using UWFBG Array and Pulse Compression: Crosstalk Analysis and Phase Noise Compensation in Space- and Time-Division Multiplexing Architectures","authors":"Cong Liu;Haozhi Wang;Ruofan Wang;Jianguan Tang;Cheng Cheng;Minghong Yang","doi":"10.1109/JLT.2025.3631875","DOIUrl":"https://doi.org/10.1109/JLT.2025.3631875","url":null,"abstract":"Distributed acoustic sensing (DAS) in complex engineering environments and large-scale applications demands multiplexing strategies capable of multipath interrogation and wideband frequency response. However, conventional interrogation using single mode fibers has difficulty in satisfying these requirements. This study establishes a high-fidelity numerical model of phase-sensitive optical time domain reflectometry (<italic>ϕ</i>-OTDR) that integrates ultra-weak fiber Bragg grating (UWFBG) array with pulse compression and phase noise compensation (PNC) technique. A detailed examination of static and dynamic crosstalk under space-division multiplexing (SDM) and time-division multiplexing (TDM) reveals the significant roles of Rayleigh backscattering and laser phase noise in limiting sensing performance. Experimental validation of PNC efficiency and crosstalk characteristics in both SDM and TDM configurations exhibits strong agreement with theoretical and numerical results. Notably, this model provides a systematic framework for evaluating crosstalk and optimizing overall system performance in DAS applications employing advanced multiplexing techniques.","PeriodicalId":16144,"journal":{"name":"Journal of Lightwave Technology","volume":"44 2","pages":"776-786"},"PeriodicalIF":4.8,"publicationDate":"2025-11-11","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145915590","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
This paper presents a PDMS-polymer based flexible diffractive optical element (DOE) for tunable beam shaping, which combine the mechanical adaptability of PDMS with the precise micro-structure formation enabled by polymer patterning. A PDMS-polymer based flexible tunable DOE is described and designed. And a detailed fabrication technology is provided for the designed DOE. The experimental results show that the fabricated flexible DOE can shape a Gaussian beam to rectangular beam. The shaped rectangular beam can be tuned by applying mechanical strain, which can introduce 0∼−32.21% length and 0∼+12.31% width variation by applying 0∼70% mechanical strain in horizontal direction, and 0∼+22.81% length and 0∼−30.97% width variation by applying 0∼70% mechanical strain in longitudinal direction. The changes in CV and diffractive efficiency of the shaped beam during this process are within an acceptable range of less than 12%. Fatigue resistance test also demonstrated that the proposed flexible DOE exhibited stable tunable performance during 500 times strain-restore, indicating excellent durability with the CV change less than 6% and diffractive efficiency change less than 2%. This approach provides a cost-effective and practical solution for dynamic beam shaping applications.
{"title":"A PDMS-Polymer Based Flexible DOE for Tunable Beam Shaping","authors":"Bowen Niu;Yanjun Hu;Qun Dai;Yu Ao;Yu Qiao;Xuanwei Xu;Xiaoyu Cai;Jiasi Wei;Yuan Li;Guofang Fan","doi":"10.1109/JLT.2025.3630640","DOIUrl":"https://doi.org/10.1109/JLT.2025.3630640","url":null,"abstract":"This paper presents a PDMS-polymer based flexible diffractive optical element (DOE) for tunable beam shaping, which combine the mechanical adaptability of PDMS with the precise micro-structure formation enabled by polymer patterning. A PDMS-polymer based flexible tunable DOE is described and designed. And a detailed fabrication technology is provided for the designed DOE. The experimental results show that the fabricated flexible DOE can shape a Gaussian beam to rectangular beam. The shaped rectangular beam can be tuned by applying mechanical strain, which can introduce 0∼−32.21% length and 0∼+12.31% width variation by applying 0∼70% mechanical strain in horizontal direction, and 0∼+22.81% length and 0∼−30.97% width variation by applying 0∼70% mechanical strain in longitudinal direction. The changes in CV and diffractive efficiency of the shaped beam during this process are within an acceptable range of less than 12%. Fatigue resistance test also demonstrated that the proposed flexible DOE exhibited stable tunable performance during 500 times strain-restore, indicating excellent durability with the CV change less than 6% and diffractive efficiency change less than 2%. This approach provides a cost-effective and practical solution for dynamic beam shaping applications.","PeriodicalId":16144,"journal":{"name":"Journal of Lightwave Technology","volume":"44 2","pages":"634-643"},"PeriodicalIF":4.8,"publicationDate":"2025-11-10","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145915624","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"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 : 2025-11-10DOI: 10.1109/JLT.2025.3630609
Yongsen Zhao;Baole Lu;Yi Yan;Chenyue Lv;Yongkang Wang;Mei Qi;Jintao Bai
Harmonic mode locking (HML) is an effective technique for generating optical pulses with high repetition rates. However, its signal-to-noise ratio (SNR) is typically limited under high-order states, hindering practical applications. In this study, we successfully generated high-SNR (>70 dB) HML pulses in an all-polarization-maintaining erbium-doped fiber laser by employing a hybrid mode-locking mechanism combining nonlinear polarization evolution (NPE) and a semiconductor saturable absorber mirror (SESAM). This approach leverages NPE's ability to stably generate high-order harmonics alongside SESAM's low mode-locking threshold. The all-polarization-maintaining design ensures environmental stability. Adjusting the pump power (120-630 mW) enables multi-order HML transitions spanning 112.86 MHz to 1.24 GHz. The 121st harmonic is the highest harmonic we have achieved so far. Even when the repetition frequency exceeds GHz and the harmonic order is over 100, it still achieves an ultra-high signal-to-noise ratio of 83.03 dB. This study provides a practical, novel solution for developing cost-effective, integrable, GHz-class ultrashort pulse sources with high SNR.
{"title":"High Signal-to-Noise Ratio GHz Harmonic Pulse Implementation Based on All Polarization-Maintaining Hybrid Mode-Locked Fiber Laser","authors":"Yongsen Zhao;Baole Lu;Yi Yan;Chenyue Lv;Yongkang Wang;Mei Qi;Jintao Bai","doi":"10.1109/JLT.2025.3630609","DOIUrl":"https://doi.org/10.1109/JLT.2025.3630609","url":null,"abstract":"Harmonic mode locking (HML) is an effective technique for generating optical pulses with high repetition rates. However, its signal-to-noise ratio (SNR) is typically limited under high-order states, hindering practical applications. In this study, we successfully generated high-SNR (>70 dB) HML pulses in an all-polarization-maintaining erbium-doped fiber laser by employing a hybrid mode-locking mechanism combining nonlinear polarization evolution (NPE) and a semiconductor saturable absorber mirror (SESAM). This approach leverages NPE's ability to stably generate high-order harmonics alongside SESAM's low mode-locking threshold. The all-polarization-maintaining design ensures environmental stability. Adjusting the pump power (120-630 mW) enables multi-order HML transitions spanning 112.86 MHz to 1.24 GHz. The 121st harmonic is the highest harmonic we have achieved so far. Even when the repetition frequency exceeds GHz and the harmonic order is over 100, it still achieves an ultra-high signal-to-noise ratio of 83.03 dB. This study provides a practical, novel solution for developing cost-effective, integrable, GHz-class ultrashort pulse sources with high SNR.","PeriodicalId":16144,"journal":{"name":"Journal of Lightwave Technology","volume":"44 2","pages":"689-695"},"PeriodicalIF":4.8,"publicationDate":"2025-11-10","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145915565","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"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 : 2025-11-06DOI: 10.1109/JLT.2025.3630006
Cong Zhang;Yu Zhen;Xinghuan Wu;Jianping Li;Yuwen Qin;Songnian Fu
Nested anti-resonant nodeless fiber (NANF) fusion splicing with variable structural parameters is essential yet challenging for both hollow-core fiber (HCF) research and field deployment. Here, we comprehensively investigate the impact of structural parameter variations on the mode field diameter (MFD) and corresponding NANF splicing performance. Numerical simulation results indicate that the air core diameter is the dominant factor in determining the MFD of NANF, and the MFD is approximately 70% of the air core diameter. Variations of the other structure parameters hold a negligible impact on the MFD. Numerical evaluation of splicing performance reveals that, under the condition of a fixed air core diameter, splicing between NANFs with different numbers of nested tube units (e.g., 5-tube and 6-tube NANF), introduces an intrinsic coupling loss (ICL) of ∼0.045 dB, attributed to the mode field shape mismatch rather than the angular alignment, as the ICL does not vary periodically with the rotational angle. Meanwhile, variations of the other parameters contribute less than 0.01 dB ICL. Finally, we conduct an experimental evaluation of fusion splicing performance by fabricating four types of NANFs with varying nested tube units, inner tube diameters, and nested tube layers. We characterize the angle alignment sensitivity, high-order mode excitation, and back-reflection performance when various combinations of four types of NANFs are fusion-spliced. Those results of NANF fusion splicing provide valuable insights for the standardization and flexible field deployment.
可变结构参数的嵌套抗谐振无节点光纤（NANF）融合拼接对于空心光纤（HCF）的研究和现场部署都是必不可少的，但也是具有挑战性的。在这里，我们全面研究了结构参数变化对模场直径（MFD）和相应的NANF拼接性能的影响。数值模拟结果表明，空气芯直径是决定纳米材料最大流通量的主要因素，最大流通量约占空气芯直径的70%。其他结构参数的变化对MFD的影响可以忽略不计。拼接性能的数值评估表明，在固定空气芯直径的条件下，具有不同嵌套管单元数量的NANF（例如，5管和6管NANF）之间的拼接引入了固有耦合损失（ICL）约0.045 dB，这归因于模式场形状不匹配而不是角对准，因为ICL不随旋转角度周期性变化。同时，其他参数的变化贡献小于0.01 dB ICL。最后，我们通过制作四种不同嵌套管单元、内管直径和嵌套管层的纳米材料，对融合拼接性能进行了实验评估。我们描述了四种类型的纳米纳米材料在不同组合融合拼接时的角度对准灵敏度、高阶模式激发和背反射性能。NANF融合拼接的结果为标准化和灵活的现场部署提供了有价值的见解。
{"title":"Fusion Splicing Performance Evaluation of Hollow-Core Fiber to Hollow-Core Fiber With Different Structural Parameters","authors":"Cong Zhang;Yu Zhen;Xinghuan Wu;Jianping Li;Yuwen Qin;Songnian Fu","doi":"10.1109/JLT.2025.3630006","DOIUrl":"https://doi.org/10.1109/JLT.2025.3630006","url":null,"abstract":"Nested anti-resonant nodeless fiber (NANF) fusion splicing with variable structural parameters is essential yet challenging for both hollow-core fiber (HCF) research and field deployment. Here, we comprehensively investigate the impact of structural parameter variations on the mode field diameter (MFD) and corresponding NANF splicing performance. Numerical simulation results indicate that the air core diameter is the dominant factor in determining the MFD of NANF, and the MFD is approximately 70% of the air core diameter. Variations of the other structure parameters hold a negligible impact on the MFD. Numerical evaluation of splicing performance reveals that, under the condition of a fixed air core diameter, splicing between NANFs with different numbers of nested tube units (e.g., 5-tube and 6-tube NANF), introduces an intrinsic coupling loss (ICL) of ∼0.045 dB, attributed to the mode field shape mismatch rather than the angular alignment, as the ICL does not vary periodically with the rotational angle. Meanwhile, variations of the other parameters contribute less than 0.01 dB ICL. Finally, we conduct an experimental evaluation of fusion splicing performance by fabricating four types of NANFs with varying nested tube units, inner tube diameters, and nested tube layers. We characterize the angle alignment sensitivity, high-order mode excitation, and back-reflection performance when various combinations of four types of NANFs are fusion-spliced. Those results of NANF fusion splicing provide valuable insights for the standardization and flexible field deployment.","PeriodicalId":16144,"journal":{"name":"Journal of Lightwave Technology","volume":"44 2","pages":"659-664"},"PeriodicalIF":4.8,"publicationDate":"2025-11-06","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145915545","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
The explosive growth of generative AI and cloud computing demands higher-speed transceivers at datacenter interconnects. Conventional wavelength-division-multiplexed (WDM) coherent systems enable large-capacity transmission but suffer from high complexity and cost due to multiple discrete components required at the transceivers. Optical frequency combs (OFCs) potentially offer a promising solution to provide cost-effective multi-wavelength sources, but compact WDM in-phase quadrature (IQ) modulators compatible with OFC sources remain undeveloped. In this paper, we present a silicon photonic WDM IQ modulator using micro-ring modulators (MRMs) for OFC-based coherent systems. Through comprehensive numerical analysis, we reveal that the 4-MRMs/$lambda$ configuration allows nearly chirp-free coherent modulation both in the over- and under-coupled MRM driving conditions. A proof-of-concept experimental demonstration is achieved using a compact silicon photonic chip containing 16 integrated MRMs. Dual-wavelength 28-Gbaud quadrature phase-shift keying signals are generated through precise tuning of resonant wavelengths of all MRMs and phase biases.
{"title":"Silicon Photonic Coherent WDM Transmitter Employing Cascaded Micro-Ring Modulators on a Mach–Zehnder Interferometer","authors":"Shuntaro Maeda;Takahiro Suganuma;Go Soma;Keita Hirashima;Takuya Okimoto;Yoshiaki Nakano;Takuo Tanemura","doi":"10.1109/JLT.2025.3629720","DOIUrl":"https://doi.org/10.1109/JLT.2025.3629720","url":null,"abstract":"The explosive growth of generative AI and cloud computing demands higher-speed transceivers at datacenter interconnects. Conventional wavelength-division-multiplexed (WDM) coherent systems enable large-capacity transmission but suffer from high complexity and cost due to multiple discrete components required at the transceivers. Optical frequency combs (OFCs) potentially offer a promising solution to provide cost-effective multi-wavelength sources, but compact WDM in-phase quadrature (IQ) modulators compatible with OFC sources remain undeveloped. In this paper, we present a silicon photonic WDM IQ modulator using micro-ring modulators (MRMs) for OFC-based coherent systems. Through comprehensive numerical analysis, we reveal that the 4-MRMs/<inline-formula><tex-math>$lambda$</tex-math></inline-formula> configuration allows nearly chirp-free coherent modulation both in the over- and under-coupled MRM driving conditions. A proof-of-concept experimental demonstration is achieved using a compact silicon photonic chip containing 16 integrated MRMs. Dual-wavelength 28-Gbaud quadrature phase-shift keying signals are generated through precise tuning of resonant wavelengths of all MRMs and phase biases.","PeriodicalId":16144,"journal":{"name":"Journal of Lightwave Technology","volume":"44 3","pages":"1061-1067"},"PeriodicalIF":4.8,"publicationDate":"2025-11-06","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://ieeexplore.ieee.org/stamp/stamp.jsp?tp=&arnumber=11231045","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"146071175","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Orbital angular momentum (OAM)-based multiplexing technology provides a novel solution for expanding optical communication capacity and enhancing spectral efficiency by leveraging an additional spatial degree of freedom. In this work, a trench-assisted non-zero dispersion-shifted seven-ring-core fiber is proposed. A single ring core can support up to the OAM4,1 mode, yielding a total of 98 OAM modes compliant with the ITU-T G.655.C standard. Within the C-band, the HE2,1 mode exhibits a minimum dispersion of 1.33 ps/nm/km, while the HE5,1 mode demonstrates a maximum dispersion of 9.08 ps/nm/km. The fiber features a large effective mode area exceeding 336 μm2 and a nonlinear coefficient below 1.97 × 10−3/W/m. In addition to enabling finer dispersion tuning, the trench structure also suppresses crosstalk between adjacent cores. When the transmission distance is 100 km, the fiber achieves below −30 dB inter-core crosstalk.
{"title":"Non-Zero Dispersion-Shifted Fiber With Seven Trench-Assisted Ring Cores for Orbital Angular Momentum Modes","authors":"Yuxiang Huang;Yuanpeng Liu;Yiwen Zhang;Wenqian Zhao;Yuetian Wang;Zhongqi Pan;Lianshan Yan;Yang Yue","doi":"10.1109/JLT.2025.3630071","DOIUrl":"https://doi.org/10.1109/JLT.2025.3630071","url":null,"abstract":"Orbital angular momentum (OAM)-based multiplexing technology provides a novel solution for expanding optical communication capacity and enhancing spectral efficiency by leveraging an additional spatial degree of freedom. In this work, a trench-assisted non-zero dispersion-shifted seven-ring-core fiber is proposed. A single ring core can support up to the OAM<sub>4,1</sub> mode, yielding a total of 98 OAM modes compliant with the ITU-T G.655.C standard. Within the C-band, the HE<sub>2,1</sub> mode exhibits a minimum dispersion of 1.33 ps/nm/km, while the HE<sub>5,1</sub> mode demonstrates a maximum dispersion of 9.08 ps/nm/km. The fiber features a large effective mode area exceeding 336 μm<sup>2</sup> and a nonlinear coefficient below 1.97 × 10<sup>−3</sup>/W/m. In addition to enabling finer dispersion tuning, the trench structure also suppresses crosstalk between adjacent cores. When the transmission distance is 100 km, the fiber achieves below −30 dB inter-core crosstalk.","PeriodicalId":16144,"journal":{"name":"Journal of Lightwave Technology","volume":"44 2","pages":"682-688"},"PeriodicalIF":4.8,"publicationDate":"2025-11-06","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"145915600","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"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 : 2025-11-06DOI: 10.1109/JLT.2025.3629543
Wassana Naku;Osamah Alsalman;Chen Zhu
Fiber Bragg gratings (FBGs) have been one of the most widely used optical fiber sensors in both scientific and industrial applications due to their unique advantages of high sensitivity, ease of signal transduction, and capabilities for remote operation and multiplexing. However, the majority of sensing systems based on FBGs can only achieve quasi-distributed sensing along the fiber under test, leaving dark zones in between discrete FBG elements. In this work, we propose and demonstrate a microwave photonics enabled approach for the interrogation of cascaded FBGs to achieve spatially distributed sensing. The core of the system includes an incoherent optical frequency-domain reflectometry module, with the assistance of a dispersive element and a joint time-frequency domain demodulation strategy. By measuring the electrical frequency response of the FBG arrays, followed by the joint time-frequency domain analysis, both the FBG elements and the optical fiber sections connecting the FBGs can be used as sensor devices based on a wavelength-to-delay-mapping technique and interferometry, respectively. Proof-of-concept experiments with a 10-FBG array (10 cm spacing) demonstrated strain sensitivities of –2.37 kHz/µϵ (interferometric channel) and –0.335 ps/µϵ (wavelength-to-delay channel), corresponding to strain resolutions of ∼10 µϵ and ∼0.9 µϵ, respectively. The approach is further shown to support hybrid WDM–TDM interrogation, offering scalability and compatibility with weak FBG arrays.
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