We propose and fabricate an unconventional photonic lantern that is not only able to achieve mode multiplexing and demultiplexing, but also has the functionality of mode-dependent loss equalization. In the process of fusion splicing between the tail fiber of photonic lantern and the few-mode fiber, by controlling the fusion splicing parameters, a refractive index (RI) modified waveguide is formed at the fusion splicing region, through which the fundamental mode will have higher attenuation than the higher-order modes, which enables us to control the attenuation of different modes, so that we can customize the unconventional photonic lantern with different differential mode attenuation (DMA). Simulation has been carried out to investigate the dependence of DMA on the structure of the RI modified waveguide, and experiments have been implemented to investigate the dependence of DMA on discharge parameters, which matches well with the simulated tendency. In addition, CCD measurements of all three output ports have been performed on the fabricated devices, well-defined mode field patterns and high mode purity at the C-band can be observed. The proposed novel unconventional photonic lanterns open a new way to obtain simultaneous mode multiplexing / demultiplexing and mode-dependent loss equalization function, which will be greatly beneficial in the few-mode fiber transmission system.
我们提出并制造了一种非常规的光子灯笼，它不仅能够实现模式复用和解复用，还具有模式相关损耗均衡功能。在光子灯笼尾纤与少模光纤熔接的过程中，通过控制熔接参数，在熔接区域形成折射率（RI）修正波导，通过该波导，基模将比高阶模具有更高的衰减，这使我们能够控制不同模式的衰减，从而定制具有不同差模衰减（DMA）的非常规光子灯笼。我们通过仿真研究了 DMA 与 RI 改进波导结构的关系，并通过实验研究了 DMA 与放电参数的关系，结果与仿真趋势吻合。此外，还对制作的器件的三个输出端口进行了 CCD 测量，可以观察到清晰的模场模式和 C 波段的高模式纯度。所提出的新型非传统光子灯笼为同时获得模式复用/解复用和模式相关损耗均衡功能开辟了一条新途径，这将大大有利于少模光纤传输系统。
{"title":"Mode-Dependent Loss Equalized Few-Mode Fiber Photonic Lantern","authors":"Yingxuan Li;Senyu Zhang;Zhiyong Zhao;Jing Liu;Zhuyixiao Liu;Ming Tang","doi":"10.1109/JPHOT.2024.3485689","DOIUrl":"https://doi.org/10.1109/JPHOT.2024.3485689","url":null,"abstract":"We propose and fabricate an unconventional photonic lantern that is not only able to achieve mode multiplexing and demultiplexing, but also has the functionality of mode-dependent loss equalization. In the process of fusion splicing between the tail fiber of photonic lantern and the few-mode fiber, by controlling the fusion splicing parameters, a refractive index (RI) modified waveguide is formed at the fusion splicing region, through which the fundamental mode will have higher attenuation than the higher-order modes, which enables us to control the attenuation of different modes, so that we can customize the unconventional photonic lantern with different differential mode attenuation (DMA). Simulation has been carried out to investigate the dependence of DMA on the structure of the RI modified waveguide, and experiments have been implemented to investigate the dependence of DMA on discharge parameters, which matches well with the simulated tendency. In addition, CCD measurements of all three output ports have been performed on the fabricated devices, well-defined mode field patterns and high mode purity at the C-band can be observed. The proposed novel unconventional photonic lanterns open a new way to obtain simultaneous mode multiplexing / demultiplexing and mode-dependent loss equalization function, which will be greatly beneficial in the few-mode fiber transmission system.","PeriodicalId":13204,"journal":{"name":"IEEE Photonics Journal","volume":"16 6","pages":"1-6"},"PeriodicalIF":2.1,"publicationDate":"2024-10-23","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://ieeexplore.ieee.org/stamp/stamp.jsp?tp=&arnumber=10733746","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142555080","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2024-10-17DOI: 10.1109/JPHOT.2024.3483209
Xin Jiang;Weilong Zhou;Wen Dong;Zhu Wang;Yifei Xie;Xinyue Tang;Zichun Le
Laser speckle caused by high coherence severely affects the image quality. The traditional optical approaches cannot effectively suppress speckles without compromising the coherence of the laser in the optical path. In this study, we develop a method in which a novel polymer-stabilized liquid crystal screen (PSLCS) was used to display images for efficient speckle suppression while preserving the coherence and high brightness of lasers. The scattering-induced fluctuations in the intensity of the light reflected from the PSLCS are evaluated to reveal decorrelation variation. The optimal parameters for suppressing speckles and obtaining a clear and high-resolution image via both laser projection and AR imaging are identified by adjusting the driving parameters. A speckle suppression efficiency of 67.34%, which exceeds that achieved by other similar methods, was achieved without using any additional optical elements. An experiment was implemented for verifying the performance of multi-plane AR imaging by a PSLCS, which, to our knowledge, is the first study to investigate the image quality and speckle suppression effect in AR imaging. The proposed cost-effective laser speckle suppression method enables high quality imaging, offering new possibilities for the application of LC-based optical materials and devices in display technology.
高相干性造成的激光斑点严重影响图像质量。传统的光学方法无法在不影响光路中激光相干性的情况下有效抑制斑点。在这项研究中，我们开发了一种方法，利用新型聚合物稳定液晶屏（PSLCS）显示图像，在保持激光相干性和高亮度的同时，有效抑制斑点。对 PSLCS 反射的光的散射引起的强度波动进行了评估，以揭示装饰相关性变化。通过调整驱动参数，确定了抑制斑点并通过激光投影和 AR 成像获得清晰、高分辨率图像的最佳参数。在不使用任何额外光学元件的情况下，斑点抑制效率达到了 67.34%，超过了其他类似方法。实验验证了 PSLCS 的多平面 AR 成像性能，据我们所知，这是首次研究 AR 成像中的图像质量和斑点抑制效果。所提出的高性价比激光斑点抑制方法实现了高质量成像，为基于 LC 的光学材料和器件在显示技术中的应用提供了新的可能性。
{"title":"Laser Speckle Suppression in Augmented Reality Displays Based on Static and Low-Loss Polymer-Stabilized Liquid Crystal Screens","authors":"Xin Jiang;Weilong Zhou;Wen Dong;Zhu Wang;Yifei Xie;Xinyue Tang;Zichun Le","doi":"10.1109/JPHOT.2024.3483209","DOIUrl":"https://doi.org/10.1109/JPHOT.2024.3483209","url":null,"abstract":"Laser speckle caused by high coherence severely affects the image quality. The traditional optical approaches cannot effectively suppress speckles without compromising the coherence of the laser in the optical path. In this study, we develop a method in which a novel polymer-stabilized liquid crystal screen (PSLCS) was used to display images for efficient speckle suppression while preserving the coherence and high brightness of lasers. The scattering-induced fluctuations in the intensity of the light reflected from the PSLCS are evaluated to reveal decorrelation variation. The optimal parameters for suppressing speckles and obtaining a clear and high-resolution image via both laser projection and AR imaging are identified by adjusting the driving parameters. A speckle suppression efficiency of 67.34%, which exceeds that achieved by other similar methods, was achieved without using any additional optical elements. An experiment was implemented for verifying the performance of multi-plane AR imaging by a PSLCS, which, to our knowledge, is the first study to investigate the image quality and speckle suppression effect in AR imaging. The proposed cost-effective laser speckle suppression method enables high quality imaging, offering new possibilities for the application of LC-based optical materials and devices in display technology.","PeriodicalId":13204,"journal":{"name":"IEEE Photonics Journal","volume":"16 6","pages":"1-10"},"PeriodicalIF":2.1,"publicationDate":"2024-10-17","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://ieeexplore.ieee.org/stamp/stamp.jsp?tp=&arnumber=10721275","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142524178","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
We proposed a DHM system with improved spatial resolution compared with that of the polarized camera-based DHM system by employing a liquid crystal phase modulator (LCPM). The LCPM-based holographic interferometry optical system can reliably construct a four-step phase shifting scheme by changing the applied voltage, thus eliminating the need for mechanical moving parts. The spatial resolution characteristics of the proposed DHM system were analyzed using the 1951 USAF resolution target. These characteristics showed a fourfold improvement over the polarized camera-based DHM system. Additionally, the 3D information capturing capability of the proposed DHM system was experimentally confirmed using a via-hole array sample produced through the semiconductor fabrication process.
{"title":"Development of a Spatial Resolution-Enhanced Digital-Hologram Microscope With a Liquid Crystal Phase Modulator","authors":"Ha-Mong Shim;Ki-Dong Lim;Min-Kyu Park;Kwang-Hoon Lee;Jin Hyeok Kim;Sungjin Lim;Kyung-Il Joo","doi":"10.1109/JPHOT.2024.3481418","DOIUrl":"https://doi.org/10.1109/JPHOT.2024.3481418","url":null,"abstract":"We proposed a DHM system with improved spatial resolution compared with that of the polarized camera-based DHM system by employing a liquid crystal phase modulator (LCPM). The LCPM-based holographic interferometry optical system can reliably construct a four-step phase shifting scheme by changing the applied voltage, thus eliminating the need for mechanical moving parts. The spatial resolution characteristics of the proposed DHM system were analyzed using the 1951 USAF resolution target. These characteristics showed a fourfold improvement over the polarized camera-based DHM system. Additionally, the 3D information capturing capability of the proposed DHM system was experimentally confirmed using a via-hole array sample produced through the semiconductor fabrication process.","PeriodicalId":13204,"journal":{"name":"IEEE Photonics Journal","volume":"16 6","pages":"1-7"},"PeriodicalIF":2.1,"publicationDate":"2024-10-16","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://ieeexplore.ieee.org/stamp/stamp.jsp?tp=&arnumber=10720202","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142524127","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
The effects of different types of fluoride glass core fibers, from three main groups of fluorozirconate (ZrF 4 -based), fluoroaluminate (AlF 3 -based), and fluoroindate (InF 3 -based) fibers, were investigated in sensing salivary cortisol utilizing surface plasmon resonance (SPR) sensors. These sensors comprised multiple layers, including fluoride glass core, metal (Ag), dielectric, and dielectric grating (SiO 2 ). The comparison was conducted to evaluate the sensor's figure of merit (FOM) and limit of detection (LOD) at 830 nm wavelength while optimizing the thickness of metal layer for different concentration of cortisol and keeping other parameters constant. The largest FOM of 20.83 RIU −1 was observed for the composition of IZBSC (40 InF 3 -20 ZnF 2 -15 BaF 2 -20 SrF 2 -5 CaF 2 ) from InF 3 -based group, resulting in an exceptional LOD of 0.986 fg/mL with the intensity interrogation method. This represents a tremendous advancement compared to prior reported results. Furthermore, by implementing a topological insulator Bi 1.5 Sb 0.5 Te 1.8 Se 1.2 (BSTS) into this sensor with a ZBLAN fiber for the first time, the LOD was reduced to 0.54 fg/mL, demonstrating remarkable progress in cortisol sensing capability best to our knowledge.
{"title":"Evaluating Different Fluoride Glass Fibers and Topological Insulator BSTS Impact on Cortisol Sensing Utilizing SPR Sensor","authors":"Fatemeh Abrishamian;Hiroyasu Sone;Kazuya Takimoto;Fua Yoshida;Musashi Nitta","doi":"10.1109/JPHOT.2024.3480249","DOIUrl":"https://doi.org/10.1109/JPHOT.2024.3480249","url":null,"abstract":"The effects of different types of fluoride glass core fibers, from three main groups of fluorozirconate (ZrF\u0000<sub>4</sub>\u0000-based), fluoroaluminate (AlF\u0000<sub>3</sub>\u0000-based), and fluoroindate (InF\u0000<sub>3</sub>\u0000-based) fibers, were investigated in sensing salivary cortisol utilizing surface plasmon resonance (SPR) sensors. These sensors comprised multiple layers, including fluoride glass core, metal (Ag), dielectric, and dielectric grating (SiO\u0000<sub>2</sub>\u0000). The comparison was conducted to evaluate the sensor's figure of merit (FOM) and limit of detection (LOD) at 830 nm wavelength while optimizing the thickness of metal layer for different concentration of cortisol and keeping other parameters constant. The largest FOM of 20.83 RIU\u0000<sup>−1</sup>\u0000 was observed for the composition of IZBSC (40 InF\u0000<sub>3</sub>\u0000-20 ZnF\u0000<sub>2</sub>\u0000-15 BaF\u0000<sub>2</sub>\u0000-20 SrF\u0000<sub>2</sub>\u0000-5 CaF\u0000<sub>2</sub>\u0000) from InF\u0000<sub>3</sub>\u0000-based group, resulting in an exceptional LOD of 0.986 fg/mL with the intensity interrogation method. This represents a tremendous advancement compared to prior reported results. Furthermore, by implementing a topological insulator Bi\u0000<sub>1.5</sub>\u0000 Sb\u0000<sub>0.5</sub>\u0000 Te\u0000<sub>1.8</sub>\u0000 Se\u0000<sub>1.2</sub>\u0000 (BSTS) into this sensor with a ZBLAN fiber for the first time, the LOD was reduced to 0.54 fg/mL, demonstrating remarkable progress in cortisol sensing capability best to our knowledge.","PeriodicalId":13204,"journal":{"name":"IEEE Photonics Journal","volume":"16 6","pages":"1-8"},"PeriodicalIF":2.1,"publicationDate":"2024-10-15","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://ieeexplore.ieee.org/stamp/stamp.jsp?tp=&arnumber=10716781","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142579208","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2024-10-11DOI: 10.1109/JPHOT.2024.3476165
Qvan Han Wang;Shuai Chang;Peng Lin;Wei Zhao;Ye Gu;Xiao Nan Yu
According to the research status of fast beam pointing and scanning in space laser communication, this paper proposes a beam deflection method that cascades liquid crystal tunable phase retarder with polarization grating, and realizes fast beam scanning and pointing according to the polarization and diffraction characteristics of light and analyzes the relationship between voltage and delay, the voltage regulation accuracy is 0.001 V, and whether the spot intensity can be used in space laser communication is verified, and the fast pointing of four spots of ±6° and ±2° is realized. The pointing accuracy is 30.49 μrad, the beam divergence angle is about 0.0339°, and it is connected to the blazed grating, and the single beam is scanned at 4.062° and 16.06° by wavelength tuning from 1525 nm to 1600 nm, with a wavelength tuning accuracy of 0.01 nm and repeated positioning accuracy of about 0.01°, which has certain research significance for the miniaturization and lightweight design of space laser communication optical transceiver and lidar.
{"title":"Research on the Deflection Characteristics of Non-Mechanical Beams of Liquid Crystal Variable Retarder Cascade Polarization Gratings","authors":"Qvan Han Wang;Shuai Chang;Peng Lin;Wei Zhao;Ye Gu;Xiao Nan Yu","doi":"10.1109/JPHOT.2024.3476165","DOIUrl":"https://doi.org/10.1109/JPHOT.2024.3476165","url":null,"abstract":"According to the research status of fast beam pointing and scanning in space laser communication, this paper proposes a beam deflection method that cascades liquid crystal tunable phase retarder with polarization grating, and realizes fast beam scanning and pointing according to the polarization and diffraction characteristics of light and analyzes the relationship between voltage and delay, the voltage regulation accuracy is 0.001 V, and whether the spot intensity can be used in space laser communication is verified, and the fast pointing of four spots of ±6° and ±2° is realized. The pointing accuracy is 30.49 μrad, the beam divergence angle is about 0.0339°, and it is connected to the blazed grating, and the single beam is scanned at 4.062° and 16.06° by wavelength tuning from 1525 nm to 1600 nm, with a wavelength tuning accuracy of 0.01 nm and repeated positioning accuracy of about 0.01°, which has certain research significance for the miniaturization and lightweight design of space laser communication optical transceiver and lidar.","PeriodicalId":13204,"journal":{"name":"IEEE Photonics Journal","volume":"16 6","pages":"1-8"},"PeriodicalIF":2.1,"publicationDate":"2024-10-11","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://ieeexplore.ieee.org/stamp/stamp.jsp?tp=&arnumber=10715521","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142825889","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2024-10-10DOI: 10.1109/JPHOT.2024.3477718
Piotr Bojęś;Piotr Jaworski;Karol Krzempek
We present the first demonstration of using the second harmonic generation effect to upconvert dissipative soliton resonance laser pulses. We have designed and built two independent dissipative soliton resonance lasers, emitting rectangular shaped, nanosecond pulses in the 1.06 μm and 1.56 μm wavelength regime, respectively. Periodically poled lithium niobate crystals with appropriate periods were used as the nonlinear medium. Dissipative soliton resonance pulses with central wavelengths of 532 nm and 780 nm and pulse energies of 0.15 μJ and 0.02 μJ were generated as the result of the second harmonic generation effects. Conversion efficiencies of 30% and 4% were obtained for conversion of 1.06 μm and 1.56 μm pulses, respectively.
{"title":"Nonlinear Frequency Conversion of Dissipative Soliton Resonance Pulses Using the Second Harmonic Generation Effect","authors":"Piotr Bojęś;Piotr Jaworski;Karol Krzempek","doi":"10.1109/JPHOT.2024.3477718","DOIUrl":"https://doi.org/10.1109/JPHOT.2024.3477718","url":null,"abstract":"We present the first demonstration of using the second harmonic generation effect to upconvert dissipative soliton resonance laser pulses. We have designed and built two independent dissipative soliton resonance lasers, emitting rectangular shaped, nanosecond pulses in the 1.06 μm and 1.56 μm wavelength regime, respectively. Periodically poled lithium niobate crystals with appropriate periods were used as the nonlinear medium. Dissipative soliton resonance pulses with central wavelengths of 532 nm and 780 nm and pulse energies of 0.15 μJ and 0.02 μJ were generated as the result of the second harmonic generation effects. Conversion efficiencies of 30% and 4% were obtained for conversion of 1.06 μm and 1.56 μm pulses, respectively.","PeriodicalId":13204,"journal":{"name":"IEEE Photonics Journal","volume":"16 6","pages":"1-8"},"PeriodicalIF":2.1,"publicationDate":"2024-10-10","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://ieeexplore.ieee.org/stamp/stamp.jsp?tp=&arnumber=10713254","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142452753","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Compared to underwater radio waves and acoustic communication technology, underwater optical communication technology has emerged as a technical means of underwater data and information transmission. Due to the complexity and volatility of the channel environment and the various factors that affect optical data transmission, there is no standard theoretical model for underwater optical wireless communication (UOWC). This work systematically evaluated and validated several optical attenuation models, leading to the development of an approach that significantly improves the accuracy of optical signal behavior prediction in underwater environments. The simulations using the Monte Carlo algorithm revealed critical insights into signal propagation, enabling more precise modeling of UOWC channels under varying conditions. We developed and validated a novel PTS-Clipping technique that effectively reduces PAPR by up to 15%, outperforming traditional methods and maintaining system efficiency. The novel PTS-Clipping approach achieved a reduction in OFDM signal PAPR from 11.861 dB to as low as 10.228 dB, demonstrating superior performance, particularly in high-order modulation schemes like 16-QAM, where signal integrity is critical. Theoretical analysis is combined with simulation experiments to promote a more robust and efficient UOWC system.
{"title":"Advancements in Underwater Optical Wireless Communication: Channel Modeling, PAPR Reduction, and Simulations With OFDM","authors":"Liwei Yang;Zeyang Bi;Xue Liang;Lihao Zhao;Jiade Zhang;Jingyi Peng","doi":"10.1109/JPHOT.2024.3475448","DOIUrl":"https://doi.org/10.1109/JPHOT.2024.3475448","url":null,"abstract":"Compared to underwater radio waves and acoustic communication technology, underwater optical communication technology has emerged as a technical means of underwater data and information transmission. Due to the complexity and volatility of the channel environment and the various factors that affect optical data transmission, there is no standard theoretical model for underwater optical wireless communication (UOWC). This work systematically evaluated and validated several optical attenuation models, leading to the development of an approach that significantly improves the accuracy of optical signal behavior prediction in underwater environments. The simulations using the Monte Carlo algorithm revealed critical insights into signal propagation, enabling more precise modeling of UOWC channels under varying conditions. We developed and validated a novel PTS-Clipping technique that effectively reduces PAPR by up to 15%, outperforming traditional methods and maintaining system efficiency. The novel PTS-Clipping approach achieved a reduction in OFDM signal PAPR from 11.861 dB to as low as 10.228 dB, demonstrating superior performance, particularly in high-order modulation schemes like 16-QAM, where signal integrity is critical. Theoretical analysis is combined with simulation experiments to promote a more robust and efficient UOWC system.","PeriodicalId":13204,"journal":{"name":"IEEE Photonics Journal","volume":"16 5","pages":"1-8"},"PeriodicalIF":2.1,"publicationDate":"2024-10-09","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://ieeexplore.ieee.org/stamp/stamp.jsp?tp=&arnumber=10713115","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142438448","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2024-10-09DOI: 10.1109/JPHOT.2024.3477311
Zhiguo Yu;Donghe Tu;Wei Yan;Huan Guan;Lei Jiang;Xuejiao Sun;Zhiyong Li
Electro-optic modulators with large bandwidth and low voltage are crucial for the high-baud-rate digital communication and high-carrier-frequency analog links. Recently, thin-film lithium niobate (TFLN) modulators with sub-1 V voltage and 140 GHz bandwidth have been emerged on the low permittivity substrates, such as quartz. However, on the high permittivity environment, such as silicon substrates, the bandwidth dramatically reduced to below 100 GHz even if the voltage was raised to around 3 V. We break the voltage–bandwidth trade-off limit in TFLN modulators on silicon substrates using low inductance thick metal traveling wave electrodes, which reduce RF phase index and microwave losses while preserving high EO modulation efficiency. We demonstrate a TFLN EO modulator on silicon substrate with 3 dB EO bandwidth $>$ 120 GHz and half-wave voltage $(V_pi) < $ 2 V. Bandwidth/ $V_pi$ reach 60, which is significantly larger than traditional TFLN modulators. The proposed thin-film lithium niobate modulators offers a practical solution for the hybrid integration of silicon and lithium niobate.
具有大带宽和低电压的电光调制器对于高波特率数字通信和高载波频率模拟链路至关重要。最近，在石英等低介电常数基底上出现了电压低于 1 V、带宽为 140 GHz 的铌酸锂薄膜（TFLN）调制器。我们利用低电感厚金属行波电极打破了硅基板上 TFLN 调制器的电压-带宽权衡限制，在保持高 EO 调制效率的同时降低了射频相位指数和微波损耗。我们在硅衬底上展示了一种 TFLN EO 调制器，其 3 dB EO 带宽为 $>$ 120 GHz，半波电压为 $(V_pi) < $ 2 V，带宽/$V_pi$达到 60，明显大于传统的 TFLN 调制器。所提出的铌酸锂薄膜调制器为硅和铌酸锂的混合集成提供了一种实用的解决方案。
{"title":"120 GHz Sub-2 V Thin-Film Lithium Niobate Modulators on Silicon Substrate Using Thick Capacitively Loaded Slow Wave Electrodes","authors":"Zhiguo Yu;Donghe Tu;Wei Yan;Huan Guan;Lei Jiang;Xuejiao Sun;Zhiyong Li","doi":"10.1109/JPHOT.2024.3477311","DOIUrl":"https://doi.org/10.1109/JPHOT.2024.3477311","url":null,"abstract":"Electro-optic modulators with large bandwidth and low voltage are crucial for the high-baud-rate digital communication and high-carrier-frequency analog links. Recently, thin-film lithium niobate (TFLN) modulators with sub-1 V voltage and 140 GHz bandwidth have been emerged on the low permittivity substrates, such as quartz. However, on the high permittivity environment, such as silicon substrates, the bandwidth dramatically reduced to below 100 GHz even if the voltage was raised to around 3 V. We break the voltage–bandwidth trade-off limit in TFLN modulators on silicon substrates using low inductance thick metal traveling wave electrodes, which reduce RF phase index and microwave losses while preserving high EO modulation efficiency. We demonstrate a TFLN EO modulator on silicon substrate with 3 dB EO bandwidth \u0000<inline-formula><tex-math>$>$</tex-math></inline-formula>\u0000 120 GHz and half-wave voltage \u0000<inline-formula><tex-math>$(V_pi) < $</tex-math></inline-formula>\u0000 2 V. Bandwidth/\u0000<inline-formula><tex-math>$V_pi$</tex-math></inline-formula>\u0000 reach 60, which is significantly larger than traditional TFLN modulators. The proposed thin-film lithium niobate modulators offers a practical solution for the hybrid integration of silicon and lithium niobate.","PeriodicalId":13204,"journal":{"name":"IEEE Photonics Journal","volume":"16 6","pages":"1-5"},"PeriodicalIF":2.1,"publicationDate":"2024-10-09","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://ieeexplore.ieee.org/stamp/stamp.jsp?tp=&arnumber=10711217","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142450992","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
The point-by point 3D scanning strategy adopted in Stimulated Emission Depletion Microscopy (STED) is time-consuming. The 3D scanning can be replaced with a 2D scanning in the non-diffracting Bessel-Bessel STED (BB-STED). In order to extract the excited emitters’ axial information in BB-STED, we propose to encode axial information by using a detection optical path with single-helix PSF, and then predict the depths of the emitters with deep learning. Simulation demonstrated that, for dense emitters in a depth range of 4 µm, an axial precision of ∼35 nm can be achieved. Our method also works for experimental data, and an axial precision of ∼63 nm can be achieved.
{"title":"Localizing Axial Dense Emitters Based on Single-Helix Point Spread Function and Deep Learning","authors":"Yihong Ji;Danni Chen;Hanzhe Wu;Gan Xiang;Heng Li;Bin Yu;Junle Qu","doi":"10.1109/JPHOT.2024.3476514","DOIUrl":"https://doi.org/10.1109/JPHOT.2024.3476514","url":null,"abstract":"The point-by point 3D scanning strategy adopted in Stimulated Emission Depletion Microscopy (STED) is time-consuming. The 3D scanning can be replaced with a 2D scanning in the non-diffracting Bessel-Bessel STED (BB-STED). In order to extract the excited emitters’ axial information in BB-STED, we propose to encode axial information by using a detection optical path with single-helix PSF, and then predict the depths of the emitters with deep learning. Simulation demonstrated that, for dense emitters in a depth range of 4 µm, an axial precision of ∼35 nm can be achieved. Our method also works for experimental data, and an axial precision of ∼63 nm can be achieved.","PeriodicalId":13204,"journal":{"name":"IEEE Photonics Journal","volume":"16 6","pages":"1-6"},"PeriodicalIF":2.1,"publicationDate":"2024-10-08","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://ieeexplore.ieee.org/stamp/stamp.jsp?tp=&arnumber=10709644","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142555081","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2024-10-07DOI: 10.1109/JPHOT.2024.3476199
Jinjin Peng;Bo Qi;Yun Zhang;ZhenChuang Li;Yao Mao
The adaptive single-mode fiber (SMF) coupling technique is normally adopted since the coupling efficiency (CE) significantly determines the performance of the free-space optical communication (FSOC) systems. The stochastic parallel gradient descent (SPGD) algorithm is the most commonly used control algorithm in adaptive SMF fiber coupling system. This paper proposes an improved SPGD algorithm named estimation-based stochastic parallel gradient descent (ESPGD) algorithm to accelerate the sytem convergence when applied to a practical adaptive SMF coupling system based on fast steering mirror (FSM). Applying the perturbed voltages, FSM dynamic response and then recording the performance metrics is the basic and most time-consuming process in actual adaptive SMF coupling system control. The ESPGD algorithm uses a different gradient estimation method based on adaptive parameter estimation method. The algorithm only needs to perform this process once in one iteration while the original SPGD algorithm needs to perform it twice to obtain the estimated gradient. This greatly reduce the time consumed by one iteration of the algorithm, thereby reducing the convergence time. The simulation and experimental results show that the ESPGD algorithm reduces the system convergence time by nearly half when correcting static angular errors and more than doubles the control bandwidth when correcting sinusoidal angular jitters.
{"title":"ESPGD Algorithm to Improve the Convergence Speed for Adaptive Single-Mode Fiber Coupling","authors":"Jinjin Peng;Bo Qi;Yun Zhang;ZhenChuang Li;Yao Mao","doi":"10.1109/JPHOT.2024.3476199","DOIUrl":"https://doi.org/10.1109/JPHOT.2024.3476199","url":null,"abstract":"The adaptive single-mode fiber (SMF) coupling technique is normally adopted since the coupling efficiency (CE) significantly determines the performance of the free-space optical communication (FSOC) systems. The stochastic parallel gradient descent (SPGD) algorithm is the most commonly used control algorithm in adaptive SMF fiber coupling system. This paper proposes an improved SPGD algorithm named estimation-based stochastic parallel gradient descent (ESPGD) algorithm to accelerate the sytem convergence when applied to a practical adaptive SMF coupling system based on fast steering mirror (FSM). Applying the perturbed voltages, FSM dynamic response and then recording the performance metrics is the basic and most time-consuming process in actual adaptive SMF coupling system control. The ESPGD algorithm uses a different gradient estimation method based on adaptive parameter estimation method. The algorithm only needs to perform this process once in one iteration while the original SPGD algorithm needs to perform it twice to obtain the estimated gradient. This greatly reduce the time consumed by one iteration of the algorithm, thereby reducing the convergence time. The simulation and experimental results show that the ESPGD algorithm reduces the system convergence time by nearly half when correcting static angular errors and more than doubles the control bandwidth when correcting sinusoidal angular jitters.","PeriodicalId":13204,"journal":{"name":"IEEE Photonics Journal","volume":"16 6","pages":"1-7"},"PeriodicalIF":2.1,"publicationDate":"2024-10-07","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://ieeexplore.ieee.org/stamp/stamp.jsp?tp=&arnumber=10707185","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142517900","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
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