The extinction ratio and insertion loss of spatial light modulator are subject to the material problem, thus limiting its applications. One reflection-type silicon-based spatial light modulator with high reflective ma...The extinction ratio and insertion loss of spatial light modulator are subject to the material problem, thus limiting its applications. One reflection-type silicon-based spatial light modulator with high reflective materials outside the Fabry-Perot cavity is demonstrated in this paper. The reflectivity values of the outside-cavity materials with different film layer numbers are simulated. The reflectivity values of 6-pair Ta2O5/SiO2 films at 1550 nm are experimentally verified to be as high as 99.9%. The surfaces of 6-pair Ta2O5/SiO2 films are smooth: their root-mean-square roughness values are as small as 0.53 nm. The insertion loss of the device at 1550 nm is only 1.2 dB. The high extinction ratio of the device at 1550 nm and 11 V is achieved to be 29.7 dB. The spatial light modulator has a high extinction ratio and low insertion loss for applications.展开更多
High-linearity electro-optic(EO)modulators play a crucial role in microwave photonics(MWP).Although various methods have been explored to enhance linearity in MWP links,they are often constrained by the intrinsic nonl...High-linearity electro-optic(EO)modulators play a crucial role in microwave photonics(MWP).Although various methods have been explored to enhance linearity in MWP links,they are often constrained by the intrinsic nonlinearity of modulator materials,the complexity of external control devices,the bulkiness of structures,and bandwidth limitations.In this study,we present an integrated thin-film lithium niobate(TFLN)linear Mach–Zehnder modulator(LMZM),showing,to our knowledge,a record-high spurious-free dynamic range(SFDR)of 121.7 dB·Hz^(4∕5)at 1 GHz with an optical power(OP)of 5.5 dBm into the photodetector(PD),based on a widebandwidth(>50 GHz)dual-optical-mode(TE0 and TE1)co-modulated configuration with just one RF input.Additionally,compared to conventional MZMs(CMZMs),the LMZM exhibits a>10.6-dB enhancement in SFDR with an OP of>−8 dBm at 1 GHz,and maintains a 6.07-dB SFDR improvement even at 20 GHz with an OP of 0 dBm.The novel LMZM,featuring high linearity,wide bandwidth,structural simplicity,and high integration,holds significant potential as a key component in future large-scale and high-performance MWP integrated circuits.展开更多
Integrated high-linearity modulators are crucial for high dynamic-range microwave photonic(MWP)systems.Conventional linearization schemes usually involve the fine tuning of radio-frequency(RF)power distribution,which ...Integrated high-linearity modulators are crucial for high dynamic-range microwave photonic(MWP)systems.Conventional linearization schemes usually involve the fine tuning of radio-frequency(RF)power distribution,which is rather inconvenient for practical applications and can hardly be implemented on the integrated photonics chip.In this paper,we propose an elegant scheme to linearize a silicon-based modulator in which the active tuning of RF power is eliminated.The device consists of two carrier-depletion-based Mach-Zehnder modulators(MZMs),which are connected in series by a 1×2 thermal optical switch(OS).The OS is used to adjust the ratio between the modulation depths of the two sub-MZMs.Under a proper ratio,the complementary third-order intermodulation distortion(IMD3)of the two sub-MZMs can effectively cancel each other out.The measured spurious-free dynamic ranges for IMD3 are 131,127,118,110,and 109 d B·Hz^(6∕7)at frequencies of 1,10,20,30,and 40 GHz,respectively,which represent the highest linearities ever reached by the integrated modulator chips on all available material platforms.展开更多
This paper presents a new method of High Resolution Range (HRR) profile formation based on Linear Frequency Modulation (LFM) signal fusion of multiple radars with multiple frequency bands. The principle of the multipl...This paper presents a new method of High Resolution Range (HRR) profile formation based on Linear Frequency Modulation (LFM) signal fusion of multiple radars with multiple frequency bands. The principle of the multiple radars signal fusion improving the range resolution is analyzed. With the analysis of return signals received by two radars,it is derived that the phase difference between the echoes varies almost linearly with respect to the frequency if the distance between two radars is neg-ligible compared with the radar observation distance. To compensate the phase difference,an en-tropy-minimization principle based compensation algorithm is proposed. During the fusion process,the B-splines interpolation method is applied to resample the signals for Fourier transform imaging. The theoretical analysis and simulations results show the proposed method can effectively increase signal bandwidth and provide a high resolution range profile.展开更多
针对高动态环境下突发信号检测问题,提出基于高阶项逐级消去的非线性调频(non-linear frequency modulation,NLFM)信号参数估计算法,利用合理近似,将其转化为相对简单的线性调频(linear frequency modulation,LFM)信号参数估计问题,并...针对高动态环境下突发信号检测问题,提出基于高阶项逐级消去的非线性调频(non-linear frequency modulation,NLFM)信号参数估计算法,利用合理近似,将其转化为相对简单的线性调频(linear frequency modulation,LFM)信号参数估计问题,并提出两级调频率逼近法用于LFM信号参数估计,具有原理简明、计算复杂度低等特点,便于实际工程应用.针对接收信号功率动态变化的问题,提出自适应快速傅里叶变换(fast Fourier transform,FFT)峰均比门限信号检测算法.仿真结果表明,所提算法能够在信噪比为-27dB的高动态环境下准确实现信号检测与参数估计.展开更多
为满足不同工业现场调校热电偶及后级控制器的需要，实现高精度温度测量，设计了多通道高精度电压转换模块。硬件系统以C8051F064为控制核心，利用AD8572等高性能芯片及军品级精密分立器件搭建线性运放电路，运用16 bit DA转换器MAX554...为满足不同工业现场调校热电偶及后级控制器的需要，实现高精度温度测量，设计了多通道高精度电压转换模块。硬件系统以C8051F064为控制核心，利用AD8572等高性能芯片及军品级精密分立器件搭建线性运放电路，运用16 bit DA转换器MAX5541实现高分辨率转换输出，用以产生符合后级测控所需的标准双极性信号。通过逐点给定0～10 V输入电压测试实物输出，实测结果证明，该模块具有稳定性好，转换精度高（可达±0.01%）等特点，完全满足不同工业现场的测控需要。展开更多
基金Project supported by the National Natural Science Foundation of China(Grant Nos.61575076 and 61804148)the National Key Research and Development Plan of China(Grant No.2016YFB0402502)
文摘The extinction ratio and insertion loss of spatial light modulator are subject to the material problem, thus limiting its applications. One reflection-type silicon-based spatial light modulator with high reflective materials outside the Fabry-Perot cavity is demonstrated in this paper. The reflectivity values of the outside-cavity materials with different film layer numbers are simulated. The reflectivity values of 6-pair Ta2O5/SiO2 films at 1550 nm are experimentally verified to be as high as 99.9%. The surfaces of 6-pair Ta2O5/SiO2 films are smooth: their root-mean-square roughness values are as small as 0.53 nm. The insertion loss of the device at 1550 nm is only 1.2 dB. The high extinction ratio of the device at 1550 nm and 11 V is achieved to be 29.7 dB. The spatial light modulator has a high extinction ratio and low insertion loss for applications.
基金National Natural Science Foundation of China(62405383)Basic and Applied Basic Research Foundation of Guangdong Province(2023A1515110666)+2 种基金Guangdong Introducing Innovative and Entrepreneurial Teams of“The Pearl River Talent Recruitment Program”(2021ZT09X044)Innovation Program for Quantum Science and Technology(2021ZD0301500)Innovation Program for Quantum Science and Technology(2021ZD0300700)。
文摘High-linearity electro-optic(EO)modulators play a crucial role in microwave photonics(MWP).Although various methods have been explored to enhance linearity in MWP links,they are often constrained by the intrinsic nonlinearity of modulator materials,the complexity of external control devices,the bulkiness of structures,and bandwidth limitations.In this study,we present an integrated thin-film lithium niobate(TFLN)linear Mach–Zehnder modulator(LMZM),showing,to our knowledge,a record-high spurious-free dynamic range(SFDR)of 121.7 dB·Hz^(4∕5)at 1 GHz with an optical power(OP)of 5.5 dBm into the photodetector(PD),based on a widebandwidth(>50 GHz)dual-optical-mode(TE0 and TE1)co-modulated configuration with just one RF input.Additionally,compared to conventional MZMs(CMZMs),the LMZM exhibits a>10.6-dB enhancement in SFDR with an OP of>−8 dBm at 1 GHz,and maintains a 6.07-dB SFDR improvement even at 20 GHz with an OP of 0 dBm.The novel LMZM,featuring high linearity,wide bandwidth,structural simplicity,and high integration,holds significant potential as a key component in future large-scale and high-performance MWP integrated circuits.
基金National Natural Science Foundation of China(62305303,62205164)Science and Technology Plan Project of Zhejiang(2022C01108)。
文摘Integrated high-linearity modulators are crucial for high dynamic-range microwave photonic(MWP)systems.Conventional linearization schemes usually involve the fine tuning of radio-frequency(RF)power distribution,which is rather inconvenient for practical applications and can hardly be implemented on the integrated photonics chip.In this paper,we propose an elegant scheme to linearize a silicon-based modulator in which the active tuning of RF power is eliminated.The device consists of two carrier-depletion-based Mach-Zehnder modulators(MZMs),which are connected in series by a 1×2 thermal optical switch(OS).The OS is used to adjust the ratio between the modulation depths of the two sub-MZMs.Under a proper ratio,the complementary third-order intermodulation distortion(IMD3)of the two sub-MZMs can effectively cancel each other out.The measured spurious-free dynamic ranges for IMD3 are 131,127,118,110,and 109 d B·Hz^(6∕7)at frequencies of 1,10,20,30,and 40 GHz,respectively,which represent the highest linearities ever reached by the integrated modulator chips on all available material platforms.
文摘This paper presents a new method of High Resolution Range (HRR) profile formation based on Linear Frequency Modulation (LFM) signal fusion of multiple radars with multiple frequency bands. The principle of the multiple radars signal fusion improving the range resolution is analyzed. With the analysis of return signals received by two radars,it is derived that the phase difference between the echoes varies almost linearly with respect to the frequency if the distance between two radars is neg-ligible compared with the radar observation distance. To compensate the phase difference,an en-tropy-minimization principle based compensation algorithm is proposed. During the fusion process,the B-splines interpolation method is applied to resample the signals for Fourier transform imaging. The theoretical analysis and simulations results show the proposed method can effectively increase signal bandwidth and provide a high resolution range profile.
文摘针对高动态环境下突发信号检测问题,提出基于高阶项逐级消去的非线性调频(non-linear frequency modulation,NLFM)信号参数估计算法,利用合理近似,将其转化为相对简单的线性调频(linear frequency modulation,LFM)信号参数估计问题,并提出两级调频率逼近法用于LFM信号参数估计,具有原理简明、计算复杂度低等特点,便于实际工程应用.针对接收信号功率动态变化的问题,提出自适应快速傅里叶变换(fast Fourier transform,FFT)峰均比门限信号检测算法.仿真结果表明,所提算法能够在信噪比为-27dB的高动态环境下准确实现信号检测与参数估计.
文摘为满足不同工业现场调校热电偶及后级控制器的需要，实现高精度温度测量，设计了多通道高精度电压转换模块。硬件系统以C8051F064为控制核心，利用AD8572等高性能芯片及军品级精密分立器件搭建线性运放电路，运用16 bit DA转换器MAX5541实现高分辨率转换输出，用以产生符合后级测控所需的标准双极性信号。通过逐点给定0～10 V输入电压测试实物输出，实测结果证明，该模块具有稳定性好，转换精度高（可达±0.01%）等特点，完全满足不同工业现场的测控需要。
