Qingshan Yu, Liguo Luo, Göran Edvell, C. Betters, Jin Wei, Simon Ellis, J. Bland-Hawthorn, Sergio Leon-Saval
Current astronomical detection of Positronium (Ps) atoms through gamma-ray emission is inherently limited by a 3-degree angular resolution. Alternatively, the triplet state of Ps is capable of producing a recombination spectrum in the near-infrared band, which would provide the potential to increase the angular resolution by a factor of 104 . The most promising signature is the Ps Balmer alpha line (Psα) at 1312.22nm. This observation scheme has never been implemented from ground-based telescopes due to the bright airglow. Now, the FBG-based OH suppression technique presents a promising solution for removing airglow emission lines surrounding the target signature. In this proceeding, we present the design and fabrication details of the first astronomy J-band FBG filters and early results of the OH suppression unit specifically developed for Ps detection.
{"title":"Aperiodic multi-notch FBG filters for astronomical positronium detection","authors":"Qingshan Yu, Liguo Luo, Göran Edvell, C. Betters, Jin Wei, Simon Ellis, J. Bland-Hawthorn, Sergio Leon-Saval","doi":"10.1117/12.3008044","DOIUrl":"https://doi.org/10.1117/12.3008044","url":null,"abstract":"Current astronomical detection of Positronium (Ps) atoms through gamma-ray emission is inherently limited by a 3-degree angular resolution. Alternatively, the triplet state of Ps is capable of producing a recombination spectrum in the near-infrared band, which would provide the potential to increase the angular resolution by a factor of 104 . The most promising signature is the Ps Balmer alpha line (Psα) at 1312.22nm. This observation scheme has never been implemented from ground-based telescopes due to the bright airglow. Now, the FBG-based OH suppression technique presents a promising solution for removing airglow emission lines surrounding the target signature. In this proceeding, we present the design and fabrication details of the first astronomy J-band FBG filters and early results of the OH suppression unit specifically developed for Ps detection.","PeriodicalId":502341,"journal":{"name":"Applied Optics and Photonics China","volume":"27 ","pages":"129650D - 129650D-9"},"PeriodicalIF":0.0,"publicationDate":"2023-12-18","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"139176239","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Maolin Chen, Xianglu Li, Jia Ye, Jie Tian, Jin Wang, Zhijiang Huang, Xinran Zhang
Dual-station cross localization method is another promising technical route to realize cooperative localization in GNSSdenied environment, requiring only two anchor node UAVs instead of at least three nodes if inter-node distance measurement based localization method is used. Traditional Angle-of Arrival (AOA) estimation techniques cannot obtain accurate and highly available angle measurements used for position calculation, for example, optical measuring equipment can provide precise angle measurements but is restricted by weather condition, array antenna can be used in all situations but its measurement error would be too large. In order to acquire precise azimuth and pitch estimations, an optical phase scanning based AOA estimation method is utilized in this work. At the remote antenna unit (RAU), one received microwave signal is applied to a phase modulator (PM), and another received microwave signal coupled with a low-frequency large-voltage sawtooth-wave signal is applied to another PM, this sawtooth-wave signal is utilized to scan the phase of the optical sideband from 0 to 2π. By transmission through a segment of fiber link, the AOA value can be measured by processing the obtained low-frequency electrical signals at the central office (CO). Experimental results demonstrate that the AOA estimation precision could be less than 2.27° when the distance between array elements is half-wavelength of the microwave (d = λ/2 0.015 @10GHz), and smaller than 0.017° if the array elements spacing is bigger than 2m for medium-sized or large-sized UAV. Then the experimental result is applied into dual station cross localization simulation structure of UAV swarm, then localization precision distribution is evaluated in different scenarios, corresponding outcomes indicate that optical phase scanning based high precision AOA estimations are beneficial to cooperative localization, and in order to acquire more accurate cooperative localization results, the positions of anchor node UAVs need to be properly adjusted.
{"title":"Hardware-in-the-loop simulation and precision evaluation of UAV swarm cooperative localization based on AOA measurement utilizing optical phase scanning","authors":"Maolin Chen, Xianglu Li, Jia Ye, Jie Tian, Jin Wang, Zhijiang Huang, Xinran Zhang","doi":"10.1117/12.3006030","DOIUrl":"https://doi.org/10.1117/12.3006030","url":null,"abstract":"Dual-station cross localization method is another promising technical route to realize cooperative localization in GNSSdenied environment, requiring only two anchor node UAVs instead of at least three nodes if inter-node distance measurement based localization method is used. Traditional Angle-of Arrival (AOA) estimation techniques cannot obtain accurate and highly available angle measurements used for position calculation, for example, optical measuring equipment can provide precise angle measurements but is restricted by weather condition, array antenna can be used in all situations but its measurement error would be too large. In order to acquire precise azimuth and pitch estimations, an optical phase scanning based AOA estimation method is utilized in this work. At the remote antenna unit (RAU), one received microwave signal is applied to a phase modulator (PM), and another received microwave signal coupled with a low-frequency large-voltage sawtooth-wave signal is applied to another PM, this sawtooth-wave signal is utilized to scan the phase of the optical sideband from 0 to 2π. By transmission through a segment of fiber link, the AOA value can be measured by processing the obtained low-frequency electrical signals at the central office (CO). Experimental results demonstrate that the AOA estimation precision could be less than 2.27° when the distance between array elements is half-wavelength of the microwave (d = λ/2 0.015 @10GHz), and smaller than 0.017° if the array elements spacing is bigger than 2m for medium-sized or large-sized UAV. Then the experimental result is applied into dual station cross localization simulation structure of UAV swarm, then localization precision distribution is evaluated in different scenarios, corresponding outcomes indicate that optical phase scanning based high precision AOA estimations are beneficial to cooperative localization, and in order to acquire more accurate cooperative localization results, the positions of anchor node UAVs need to be properly adjusted.","PeriodicalId":502341,"journal":{"name":"Applied Optics and Photonics China","volume":"82 ","pages":"129660U - 129660U-18"},"PeriodicalIF":0.0,"publicationDate":"2023-12-18","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"139176291","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Shuguang Li, K. Guo, Kaili Qin, Tingyao Xie, Lele Zhu, Xi Ye, Zhenbin Lv, Wenbin Lu
Demonstration of LFMCW radar system by hardware-in-the-loop simulation based on tunable microwave photonics generated radar signal and electric receiving link is presented. The seed signal is given by Direct Digital Synthesis (DDS) with tunable signal wave forms, which can afford the system with different time-width and bandwidth. The microwave photonics electro-optic modulation and photoelectric transformation system turns the seed signal with low-frequency and narrow-bandwidth into the signal by 4 times at frequency carried on the laser through the dualparallel electro-optic modulator, and obtain the high-frequency and broadband radar signal after the photoelectric detector, and then transmit the radar signal into the input port of the hardware-in-the-loop simulator with time delay function. The radar signal is set as different delay corresponding to different transmission distance, such as 1km, 2km, and other distances. After the hardware-in-the-loop simulator with some distance delay, the signal is transmitted from the output ort of the hardware-in-the-loop simulator into the receiver. In the receiving link, the electric de-chirping method is carried out to down convert the radar echo signal. After electric ADC, the ranging data is processed. Two typical wave forms, such as the wave form with 1GHz bandwidth and 2ms pulse width, and the other wave form with 2GHz bandwidth and 8ms are operated through the system respectively. The demonstration by hardware-in-the-loop simulation has been given, and the experimental results show that the range of frequency modulated continuous wave radar based on this system can reach 5 km.
{"title":"Demonstration of MWP radar by hardware-in-the-loop simulation based on tunable MWP generated signal and electric receiving link","authors":"Shuguang Li, K. Guo, Kaili Qin, Tingyao Xie, Lele Zhu, Xi Ye, Zhenbin Lv, Wenbin Lu","doi":"10.1117/12.3007820","DOIUrl":"https://doi.org/10.1117/12.3007820","url":null,"abstract":"Demonstration of LFMCW radar system by hardware-in-the-loop simulation based on tunable microwave photonics generated radar signal and electric receiving link is presented. The seed signal is given by Direct Digital Synthesis (DDS) with tunable signal wave forms, which can afford the system with different time-width and bandwidth. The microwave photonics electro-optic modulation and photoelectric transformation system turns the seed signal with low-frequency and narrow-bandwidth into the signal by 4 times at frequency carried on the laser through the dualparallel electro-optic modulator, and obtain the high-frequency and broadband radar signal after the photoelectric detector, and then transmit the radar signal into the input port of the hardware-in-the-loop simulator with time delay function. The radar signal is set as different delay corresponding to different transmission distance, such as 1km, 2km, and other distances. After the hardware-in-the-loop simulator with some distance delay, the signal is transmitted from the output ort of the hardware-in-the-loop simulator into the receiver. In the receiving link, the electric de-chirping method is carried out to down convert the radar echo signal. After electric ADC, the ranging data is processed. Two typical wave forms, such as the wave form with 1GHz bandwidth and 2ms pulse width, and the other wave form with 2GHz bandwidth and 8ms are operated through the system respectively. The demonstration by hardware-in-the-loop simulation has been given, and the experimental results show that the range of frequency modulated continuous wave radar based on this system can reach 5 km.","PeriodicalId":502341,"journal":{"name":"Applied Optics and Photonics China","volume":"26 1","pages":"129661X - 129661X-5"},"PeriodicalIF":0.0,"publicationDate":"2023-12-18","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"139173106","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
With the rapid advancement of space astronomical observation technology, there is an increasing demand for higher camera imaging quality. The micro-vibrations generated by internal disturbances of the satellite platform are the primary factors affecting encircled energy of disc of confusion in star image point. The traditional optical image stabilization system compensates for the disturbance by acquiring the variation of the centroid coordinates of the image point as an error feedback of the system, which has the problems of obvious lag and insufficient rapid response ability. To overcome the problem, a method based on optical image stabilization system for predicting angular velocity was proposed and on the basis of measuring the angular velocity of the Satellite bus as the error feedback of the systemin this paper. The measured data are predicted using a combination of current statistical model (CS) and Kalman filtering algorithm. The simulation results in MATLAB demonstrate that the image stabilization system's line of sight stabilization is better than1".It is shown that the method proposed in this paper has feasibility in the optical image stabilization system, the proposed algorithm has the characteristics of high robust and low computing load, and can accurately and effectively predict the vibration information of satellite platform in advance, and provide help for the rapid implementation of vibration suppression measures.
{"title":"Application of satellite platform angular velocity prediction based on Kalman filter in optical image stabilization system","authors":"Qifan Cheng, Yan Wen, Wencan Li","doi":"10.1117/12.3007599","DOIUrl":"https://doi.org/10.1117/12.3007599","url":null,"abstract":"With the rapid advancement of space astronomical observation technology, there is an increasing demand for higher camera imaging quality. The micro-vibrations generated by internal disturbances of the satellite platform are the primary factors affecting encircled energy of disc of confusion in star image point. The traditional optical image stabilization system compensates for the disturbance by acquiring the variation of the centroid coordinates of the image point as an error feedback of the system, which has the problems of obvious lag and insufficient rapid response ability. To overcome the problem, a method based on optical image stabilization system for predicting angular velocity was proposed and on the basis of measuring the angular velocity of the Satellite bus as the error feedback of the systemin this paper. The measured data are predicted using a combination of current statistical model (CS) and Kalman filtering algorithm. The simulation results in MATLAB demonstrate that the image stabilization system's line of sight stabilization is better than1\".It is shown that the method proposed in this paper has feasibility in the optical image stabilization system, the proposed algorithm has the characteristics of high robust and low computing load, and can accurately and effectively predict the vibration information of satellite platform in advance, and provide help for the rapid implementation of vibration suppression measures.","PeriodicalId":502341,"journal":{"name":"Applied Optics and Photonics China","volume":"58 3","pages":"129630Z - 129630Z-6"},"PeriodicalIF":0.0,"publicationDate":"2023-12-18","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"139173125","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Xuefei Zhao, Shanshan Wang, Nansheng Zhang, Qun Hao, Feng Shi
As a kind of common aspheric element, high-gradient aspheric surface is more and more used in high-tech fields because of its advantages of improving system accuracy and optimizing system comprehensive performance. At the same time, it also has higher requirements for its surface processing quality. The trajectory planning in polishing is an important part that affects the surface quality of the component. Due to the continuous change of the curvature radius of the high-steep aspheric surface and the large change rate of the vector height, the commonly used planar equidistant grating scanning trajectory is projected onto its surface. The distribution of trajectory points on the surface is obviously uneven, resulting in over polishing or under polishing in some areas. In order to ensure the machining accuracy of high-gradient aspheric surface, the concept of “common equal arc length point” is proposed and the equal arc length trajectory point planning model is established to make the spatial distance of any adjacent trajectory points on the aspheric surface consistent, and the spatial interval change rate is introduced to quantitatively analyze the distribution of trajectory points. Several aspheric surfaces with different vector height change rates are sampled by the equal arc length trajectory point model. Under the same sampling accuracy as the plane equidistant grid scanning trajectory point model, the change rate of the trajectory point spacing to the surface shape is reduced from 70.72 % ~ 33.03 %to 25.18%~8.75 %. The simulation results show the effectiveness of the model.
{"title":"High steepness aspheric polishing trajectory planning based on equal arc length sampling","authors":"Xuefei Zhao, Shanshan Wang, Nansheng Zhang, Qun Hao, Feng Shi","doi":"10.1117/12.3000163","DOIUrl":"https://doi.org/10.1117/12.3000163","url":null,"abstract":"As a kind of common aspheric element, high-gradient aspheric surface is more and more used in high-tech fields because of its advantages of improving system accuracy and optimizing system comprehensive performance. At the same time, it also has higher requirements for its surface processing quality. The trajectory planning in polishing is an important part that affects the surface quality of the component. Due to the continuous change of the curvature radius of the high-steep aspheric surface and the large change rate of the vector height, the commonly used planar equidistant grating scanning trajectory is projected onto its surface. The distribution of trajectory points on the surface is obviously uneven, resulting in over polishing or under polishing in some areas. In order to ensure the machining accuracy of high-gradient aspheric surface, the concept of “common equal arc length point” is proposed and the equal arc length trajectory point planning model is established to make the spatial distance of any adjacent trajectory points on the aspheric surface consistent, and the spatial interval change rate is introduced to quantitatively analyze the distribution of trajectory points. Several aspheric surfaces with different vector height change rates are sampled by the equal arc length trajectory point model. Under the same sampling accuracy as the plane equidistant grid scanning trajectory point model, the change rate of the trajectory point spacing to the surface shape is reduced from 70.72 % ~ 33.03 %to 25.18%~8.75 %. The simulation results show the effectiveness of the model.","PeriodicalId":502341,"journal":{"name":"Applied Optics and Photonics China","volume":"240 1","pages":"1296403 - 1296403-10"},"PeriodicalIF":0.0,"publicationDate":"2023-12-18","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"139173257","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Jinlong Lu, Ting Hao, Zhihao Li, Dennis Zhou, Guijun Ji, Xinglong Wang
A filling material based on a similar refractive index with SiN is designed as the mode converter for thin film lithium niobate (TFLN). Such a design can realize an output mode field compatible with different sizes ranging from 3.5 um-9.2 um. The double-layer mode converter core with SiN has a similar height as the ridge waveguide of TFLN, which is helpful to increase the conversion efficiency. An overall coupling loss of less than 0.6 dB was achieved theoretically at 1310 nm for both modes. The proposed scheme avoids the disadvantage of high reflection when the inclined TFLN section result from dry-etching is directly used as the coupling end face and can improve the performance of integrated TFLN electro-optic modulation on the chip level. Three-dimensional simulation results show that the designed structure is insensitive to fabrication tolerance, which provides a feasible solution for reducing the volume of integrated devices, increasing overall performance and high-density integration.
我们设计了一种基于与 SiN 相似折射率的填充材料，作为铌酸锂薄膜（TFLN）的模式转换器。这种设计可以实现与 3.5 um-9.2 um 不同尺寸兼容的输出模式场。采用 SiN 的双层模式转换器核心与 TFLN 的脊波导高度相似，这有助于提高转换效率。理论上，在 1310 nm 波长处，两种模式的整体耦合损耗均小于 0.6 dB。所提出的方案避免了直接使用干蚀刻产生的倾斜 TFLN 截面作为耦合端面时反射率高的缺点，可以提高芯片级集成 TFLN 光电调制的性能。三维仿真结果表明，所设计的结构对制造公差不敏感，为减小集成器件体积、提高整体性能和高密度集成提供了可行的解决方案。
{"title":"High-efficiency mode converters compatible with different mode fields for thin film lithium niobate","authors":"Jinlong Lu, Ting Hao, Zhihao Li, Dennis Zhou, Guijun Ji, Xinglong Wang","doi":"10.1117/12.3006735","DOIUrl":"https://doi.org/10.1117/12.3006735","url":null,"abstract":"A filling material based on a similar refractive index with SiN is designed as the mode converter for thin film lithium niobate (TFLN). Such a design can realize an output mode field compatible with different sizes ranging from 3.5 um-9.2 um. The double-layer mode converter core with SiN has a similar height as the ridge waveguide of TFLN, which is helpful to increase the conversion efficiency. An overall coupling loss of less than 0.6 dB was achieved theoretically at 1310 nm for both modes. The proposed scheme avoids the disadvantage of high reflection when the inclined TFLN section result from dry-etching is directly used as the coupling end face and can improve the performance of integrated TFLN electro-optic modulation on the chip level. Three-dimensional simulation results show that the designed structure is insensitive to fabrication tolerance, which provides a feasible solution for reducing the volume of integrated devices, increasing overall performance and high-density integration.","PeriodicalId":502341,"journal":{"name":"Applied Optics and Photonics China","volume":"116 ","pages":"129661B - 129661B-6"},"PeriodicalIF":0.0,"publicationDate":"2023-12-18","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"139173651","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
The coupling efficiency between the backscattering light field received by the telescope and the single-mode fiber is one of the important parameters affecting the performance of the all-fiber water vapor Raman lidar system. In the process of using Raman lidar to detect water vapor, the telescope receives the backscattered light signal of the system, which is focused and coupled into the single-mode fiber through the microscopic objective lens. The mode field diameter of the selected single-mode fiber is only 4μm. The weak offset will lead to a decrease in coupling efficiency. When the no-load or space-borne lidar detects the atmosphere, the fluctuation of the airflow may cause the platform vibration to produce a position offset, which will reduce the efficiency of coupling the water vapor Raman scattering echo signal into the single-mode fiber. Based on the above problems, this paper designs a single-mode fiber automatic coupling system. In the closed-loop mode, the controller uses the piezoelectric effect to control the three-axis motion platform to automatically track the maximum brightness in the shooting spot, and realizes the coupling alignment between the single-mode fiber and the nitrogen Raman scattering echo (386.7nm) and the water vapor Raman scattering echo (407.8nm). The coupling efficiency is 49.7%, and the automatic adjustment accuracy is sub-micron. The influence of axial offset and lateral offset on the coupling efficiency is analyzed at the incident light wavelength of 407 nm. This provides a new solution for the continuous, stable and efficient acquisition of water vapor signals by all-fiber detection water vapor Raman lidar system.
{"title":"Design of automatic coupling system based on all-fiber water vapor Raman lidar","authors":"Hui Li, Xin Gong","doi":"10.1117/12.3000667","DOIUrl":"https://doi.org/10.1117/12.3000667","url":null,"abstract":"The coupling efficiency between the backscattering light field received by the telescope and the single-mode fiber is one of the important parameters affecting the performance of the all-fiber water vapor Raman lidar system. In the process of using Raman lidar to detect water vapor, the telescope receives the backscattered light signal of the system, which is focused and coupled into the single-mode fiber through the microscopic objective lens. The mode field diameter of the selected single-mode fiber is only 4μm. The weak offset will lead to a decrease in coupling efficiency. When the no-load or space-borne lidar detects the atmosphere, the fluctuation of the airflow may cause the platform vibration to produce a position offset, which will reduce the efficiency of coupling the water vapor Raman scattering echo signal into the single-mode fiber. Based on the above problems, this paper designs a single-mode fiber automatic coupling system. In the closed-loop mode, the controller uses the piezoelectric effect to control the three-axis motion platform to automatically track the maximum brightness in the shooting spot, and realizes the coupling alignment between the single-mode fiber and the nitrogen Raman scattering echo (386.7nm) and the water vapor Raman scattering echo (407.8nm). The coupling efficiency is 49.7%, and the automatic adjustment accuracy is sub-micron. The influence of axial offset and lateral offset on the coupling efficiency is analyzed at the incident light wavelength of 407 nm. This provides a new solution for the continuous, stable and efficient acquisition of water vapor signals by all-fiber detection water vapor Raman lidar system.","PeriodicalId":502341,"journal":{"name":"Applied Optics and Photonics China","volume":"175 ","pages":"129620J - 129620J-10"},"PeriodicalIF":0.0,"publicationDate":"2023-12-18","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"139174540","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
In view of the demand for multi-format modulated signals from multifunctional radar, a reconfigurable pulse compression signal generation scheme based on dual-parallel Quadrature Phase Shift Keying modulator (DP-QPSK) is proposed. In this scheme, the phase coded signal and linear frequency modulation signal can be switched by changing the encoding format of the input electrical signal without altering the link structure. To generate pulse signals with flexible and tunable carrier frequencies, optical filtering is not employed in this scheme. Simulation results demonstrate that the proposed scheme successfully achieves the switching between phase-encoded signals and linear frequency modulation signals, and the Peak-to-side Ratios (PSR) and Pulse Compression Ratios (PCR) of the generated signals closely approximate.
{"title":"Reconfigurable pulse-compression signal generation based on DP-QPSK modulator","authors":"Jialin Ma, Hang Hu, Yuetong Zhang","doi":"10.1117/12.3007024","DOIUrl":"https://doi.org/10.1117/12.3007024","url":null,"abstract":"In view of the demand for multi-format modulated signals from multifunctional radar, a reconfigurable pulse compression signal generation scheme based on dual-parallel Quadrature Phase Shift Keying modulator (DP-QPSK) is proposed. In this scheme, the phase coded signal and linear frequency modulation signal can be switched by changing the encoding format of the input electrical signal without altering the link structure. To generate pulse signals with flexible and tunable carrier frequencies, optical filtering is not employed in this scheme. Simulation results demonstrate that the proposed scheme successfully achieves the switching between phase-encoded signals and linear frequency modulation signals, and the Peak-to-side Ratios (PSR) and Pulse Compression Ratios (PCR) of the generated signals closely approximate.","PeriodicalId":502341,"journal":{"name":"Applied Optics and Photonics China","volume":"134 ","pages":"129661F - 129661F-10"},"PeriodicalIF":0.0,"publicationDate":"2023-12-18","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"139174663","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Fengyun Li, Nian Liu, J. Dai, Chun Zhang, Cong Gao, Rumao Tao, Lingli Huang
In a recent experimental study, we investigated a homemade distributed side-coupled cladding-pumped (DSCCP) fiber using a master oscillator power amplifier (MOPA) configuration and tandem-pumping technique. During the experiment, we observed an abnormal behavior of the residual pump power from the counter port of the pump core. This abnormal behavior exhibited a threshold-like characteristic, with both the residual power and corresponding power ratio to injected pump starting to increase exponentially above a specific value. Specifically, when the pump power injected into the system ranged from 7.2 kW to 11.77 kW, the corresponding residual power ratio increased from 4.05% to 11.01%. Simultaneously, the signal optical-to-optical conversion efficiency decreased from 84.11% to 75.33%. This sudden appearance of the phenomenon significantly limits the ability to further scale the power of the system. However, the underlying mechanism causing this abnormal behavior remains unclear and requires further investigation.
{"title":"Abnormal residual pump behavior in homemade DSCCP fiber","authors":"Fengyun Li, Nian Liu, J. Dai, Chun Zhang, Cong Gao, Rumao Tao, Lingli Huang","doi":"10.1117/12.3007996","DOIUrl":"https://doi.org/10.1117/12.3007996","url":null,"abstract":"In a recent experimental study, we investigated a homemade distributed side-coupled cladding-pumped (DSCCP) fiber using a master oscillator power amplifier (MOPA) configuration and tandem-pumping technique. During the experiment, we observed an abnormal behavior of the residual pump power from the counter port of the pump core. This abnormal behavior exhibited a threshold-like characteristic, with both the residual power and corresponding power ratio to injected pump starting to increase exponentially above a specific value. Specifically, when the pump power injected into the system ranged from 7.2 kW to 11.77 kW, the corresponding residual power ratio increased from 4.05% to 11.01%. Simultaneously, the signal optical-to-optical conversion efficiency decreased from 84.11% to 75.33%. This sudden appearance of the phenomenon significantly limits the ability to further scale the power of the system. However, the underlying mechanism causing this abnormal behavior remains unclear and requires further investigation.","PeriodicalId":502341,"journal":{"name":"Applied Optics and Photonics China","volume":"50 ","pages":"1295917 - 1295917-4"},"PeriodicalIF":0.0,"publicationDate":"2023-12-18","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"139175721","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Liao Ye, Haoran Ma, Maohui Li, Fanjie Ruan, Jianyi Yang
We propose and demonstrate a sub-gigahertz bandwidth photonic differentiator employing the self-induced optical modulation effect in a silicon-on-insulator micro-ring resonator. The all-passive DIFF is controlled through an all-optical pump-probe scheme. Input Gaussian-like pulses with 7.5ns pulse width are differentiated at high processing accuracy. A semi-analytical model that agrees with the experimental results is also derived. The DIFF’s energy efficiency is higher than 45%, far surpassing all previously reported schemes for sub-gigahertz bandwidth pulses. Our scheme expands the application potential of photonic DIFFs.
{"title":"Photonic differentiator employing self-induced optical modulation effect","authors":"Liao Ye, Haoran Ma, Maohui Li, Fanjie Ruan, Jianyi Yang","doi":"10.1117/12.3007979","DOIUrl":"https://doi.org/10.1117/12.3007979","url":null,"abstract":"We propose and demonstrate a sub-gigahertz bandwidth photonic differentiator employing the self-induced optical modulation effect in a silicon-on-insulator micro-ring resonator. The all-passive DIFF is controlled through an all-optical pump-probe scheme. Input Gaussian-like pulses with 7.5ns pulse width are differentiated at high processing accuracy. A semi-analytical model that agrees with the experimental results is also derived. The DIFF’s energy efficiency is higher than 45%, far surpassing all previously reported schemes for sub-gigahertz bandwidth pulses. Our scheme expands the application potential of photonic DIFFs.","PeriodicalId":502341,"journal":{"name":"Applied Optics and Photonics China","volume":"36 6","pages":"1296626 - 1296626-4"},"PeriodicalIF":0.0,"publicationDate":"2023-12-18","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"139175826","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
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