共查询到18条相似文献,搜索用时 218 毫秒
1.
提出一种基于注入锁定和锁相环技术的注入锁相光电振荡器.利用注入锁定来改善光电振荡器的近载频相噪以及杂散抑制度.将光电振荡器的输出信号与外注入源进行鉴相,通过锁相环来提升频率稳定性,并进一步改善光电振荡器的近载频相噪.实验结果表明:注入锁相光电振荡器在电滤波器中心频率为9.5GHz、3dB带宽为20 MHz和光纤环长度为6km的情况下,实现了输出信号频率为9.5GHz的单模振荡;当注入锁定带宽为1.98kHz时,光电振荡器输出信号在1kHz频偏处的相位噪声为-125dBc/Hz,在10kHz频偏处的相位噪声为-147dBc/Hz,杂散抑制度高于80dB,阿伦偏差接近1.37×10~(-11)@1s和1.22×10~(-11)@1000s. 相似文献
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提出了一种基于受激布里渊散射和耦合型双环的可调谐光电振荡器.该光电振荡器将受激布里渊散射和耦合型双环结构相结合,利用受激布里渊散射的窄带增益谱选择振荡频率,实现微波信号的频率可调谐.通过耦合型双环结构,有效地抑制了微波信号的边模,降低了微波信号的相位噪声,提高了微波信号的频率和功率稳定性.实验结果表明,该结构的光电振荡器可以产生2GHz到18GHz的微波信号,边模抑制比优于60dB,相位噪声在10kHz频偏处低于-95dBc/Hz,在实验室环境下10GHz微波信号30min内频率漂移小于0.3ppm,功率漂移低于0.2dB. 相似文献
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提出了一种利用电光调制器的非线性效应实现光电振荡器倍频输出的方法,通过在光电振荡环路中引入微波分频器,使得利用低频率的电光调制器有可能产生高频率的微波倍频信号输出,从而降低了振荡频率对调制器工作频率的要求。理论和实验研究表明,在微波信号输入功率较低时,调制器将引入较大的附加噪声,会严重恶化光电振荡器输出的倍频微波信号的相位噪声。通过在振荡反馈环路中增加一个微波放大器,减小附加噪声,能够极大地改善倍频信号的相位噪声。当环路光纤为1km时,产生的9GHz倍频信号相位噪声在10kHz频率偏移时达到-104dBc/Hz,比典型光电振荡环路恶化了6dB,同时,保持了较高的输出功率。实验结果与理论分析基本一致,证明了该倍频输出光电振荡器的可行性。 相似文献
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针对传统大功率Si,GaAs固态微波源效率低和高温度性能差的不足,采用导热系数优良的宽禁带GaN单元功放模块集成、低损耗同轴波导径向空间功率合成方法,研制出一种1.2kW全固态C波段高效率宽禁带GaN微波源。实验结果表明:该方法实现了大功率固态微波源高效率及连续长时间高温风冷散热运行,系统安全可靠。单路功放模块集成6位移相器,移相精度5.6°,增益35dB,输出功率大于31W。系统连续波输出功率1.2kW,总效率30%,谐波抑制-54.8dBc;杂散-63.69dBc,相位噪声-94.03dBc/Hz@1kHz。 相似文献
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提出了一种利用单光源光电振荡器(OEO)结构实现多波长光脉冲输出的方案.通过一个直调光源和光谱切片技术在OEO腔内可以产生不同中心波长的光脉冲和电时钟信号.腔内多个波跃通道自然形成的多环路结构可以有效地抑制信号边模.在5 GHz频率的实验演示中,该系统产生了脉宽约10 ps,抖动1 ps的单波长脉冲、20 GHz(4×5 GHz)的时分复用脉冲与波/时分复用脉冲.所得到电时钟信号的相位噪声在频偏10 kHz处为-113 dBc/Hz,边模抑制比为100 dBc/HZ. 相似文献
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提出了一种新型的基于光电振荡器的重复频率可调谐的超低抖动光窄脉冲源. 光电振荡器系统可以产生超低相位噪声的微波信号; 被该信号调制的直调光经过两次相位调制之后, 使光脉冲的啁啾增强; 再通过一段色散补偿光纤, 光脉冲被进一步压窄. 实验中使用YIG可调滤波器, 可以得到8–12 GHz内步进为200 MHz的可调谐微波信号, 因此光脉冲的重复频率具有可调谐性. 当微波信号即脉冲重复频率为9.6 GHz时, 测得脉冲宽度为3.7 ps, 相位噪声为-130.1 dBc/Hz@10 kHz. 由此得出光脉冲的瞬时抖动为60.1 fs (100 Hz–1 MHz), 因此该方案产生的光窄脉冲源具有超低的抖动. 相似文献
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芯片级原子钟主要包括射频模块、物理封装模块以及其他的外围控制模块。射频模块的设计关系到芯片级原子钟的短期稳定度,所以射频模块在芯片级原子钟的设计时是非常重要的一部分。本文利用数字锁相环技术实现频率为4.596 GHz的射频源,射频源由三部分组成,包括小数分频频率综合器、压控振荡器和环路滤波器。数字锁相环具有相位噪声低,频谱稳定度高等特点。此外,由于小数分频频率综合器是可编程的,可以通过配置N分频器与R分频器实现输出频率的快速扫描。与此同时,根据相关公式,可以计算出三阶无源环路滤波器的近似参数值,所设计的环路滤波器具有300 kHz的环路带宽以及55的相位裕度。最后,整个基于数字锁相环技术实现的射频源通过仿真、硬件实现以及测试。测试结果显示,射频源的相位噪声为-74.02 dBc/Hz@300 Hz,符合芯片级原子钟射频源的设计要求。 相似文献
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Yonghong Zhang Xiaohong Tang Yong Fan Zhengde Wu 《International Journal of Infrared and Millimeter Waves》2006,27(8):1087-1093
A W-band millimeter wave frequency source is developed by frequency multiplier chain and injection locking. The referenced
crystal oscillator (CO) signal 120 MHz is multiplied 400 times to output 48 GHz signal. Then, it is used as a referenced source
of fundamental-wave injection-locked harmonic Gunn oscillator with output power more than 10 mW at 96 GHz and spurious output
less than −65 dBc. The measured phase noise is −97 and −105 dBc/Hz at 10 kHz and 200 kHz offset, respectively. At last, the
influence of the flicker noise, provided by the frequency multipliers and amplifiers, is analyzed. 相似文献
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Yonghong Zhang Xiaohong Tang Yong Fan Zhengde Wu 《International Journal of Infrared and Millimeter Waves》2008,29(2):142-147
A W-band coherent stepped-frequency pulsed radar front-end is developed. It consists of a millimetre wave transmitting source,
a mm-wave local source, a DDS with multi frequency points output and two microwave sources serving as local oscillators. All
the sources are coherent with the 120 MHz referenced crystal oscillator. The mm-wave sources are realized by frequency multiplier
chain, up-conversion and injection locking. The phase noise of fundamental-wave injection-locked W-band harmonic Gunn oscillator
output signal achieves −98 dBc/Hz at 10 kHz offset and the spurious output is less than −50 dBc. The received intermediate
frequency signal is also presented. 相似文献
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We synchronize an 8.06 GHz microwave signal from a voltage-controlled oscillator with an optical pulse train from a 77.5 MHz mode-locked Er-fiber laser using a fiber-based optical-microwave phase detector. The residual phase noise between the optical pulse train and the synchronized microwave signal is -133 dBc/Hz (-154 dBc/Hz) at 1 Hz (5 kHz) offset frequency, which results in 838 as integrated rms timing jitter [1 Hz-1 MHz]. The long-term residual phase drift is 847 as (rms) measured over 2 h, which reaches 4×10(-19) fractional frequency instability at 1800 s averaging time. This method has a potential to provide both subfemtosecond-level short-term phase noise and long-term phase stability in microwave extraction from mode-locked fiber lasers. 相似文献
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Quinlan F Fortier TM Kirchner MS Taylor JA Thorpe MJ Lemke N Ludlow AD Jiang Y Diddams SA 《Optics letters》2011,36(16):3260-3262
We present an optical frequency divider based on a 200 MHz repetition rate Er:fiber mode-locked laser that, when locked to a stable optical frequency reference, generates microwave signals with absolute phase noise that is equal to or better than cryogenic microwave oscillators. At 1 Hz offset from a 10 GHz carrier, the phase noise is below -100 dBc/Hz, limited by the optical reference. For offset frequencies >10 kHz, the phase noise is shot noise limited at -145 dBc/Hz. An analysis of the contribution of the residual noise from the Er:fiber optical frequency divider is also presented. 相似文献
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Optically generated 20-GHz microwave carriers with phase noise lower than -75 dBc/Hz at 10 kHz offset and lower than -90 dBc/Hz at 100 kHz offset are obtained using single- and double-sideband injection locking. Within the locking range, the effect of sideband injection locking can be regarded as narrow-band amplification of the modulation sidebands. Increasing the current of slave laser will increase the power of beat signal and reduce the phase noise to a certain extent. Double-sideband injection locking can increase the power of the generated microwave carrier while keeping the phase noise at a low level. It is also revealed that partially destruction of coherence between the two beating lights in the course of sideband injection locking would impair the phase noise performance. 相似文献
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随着无线通信的速率提升和微蜂窝趋势,光载微波技术已经成为重要的发展趋势,而光生多载波系统是光载微波的最重要的技术之一.本文提出了一种基于双环混频光电振荡器(OEO)的可调谐光载微波频率梳产生方案,可同时实现多频段微波信号产生,从而高效低成本地为无线节点提供光生微波载波.方案采用混频双环OEO系统,通过工作在增益开关状态的直调激光器,利用其非线性动态特性产生多频率光载微波频率梳信号,并采用双路微波滤波器分别滤出两个相邻频率的微波信号,并利用二者的差频反馈注入直调激光器构成光电谐振.利用偏振双环结构抑制长谐振腔引起的边模问题,提高了输出信号的噪声特性.经过实验分析,得到了低相噪的多路微波信号,并最终实现了间隔797.4 MHz的稳定的微波频率梳信号,一阶载波相位噪声低于-101.7 dBc/Hz@10 kHz,-115.2 dBc/Hz@50 kHz.因此该方案产生的光载微波频率梳信号具有低噪声的优点,适用于光载微波通信系统. 相似文献
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Two-level injection-locked opto-electronic oscillator is proposed for low phase noise. Dielectric resonator oscillator (DRO) is used as the first injection source, injection locking a long-fiber loop based opto-electronic oscillator, then its output is injection locking another long-fiber opto-electronic oscillator for getting a lower-phase noise output carrier. After the first injection, the single side band (SSB) phase noise at 10 kHz offset frequency decreases from −123 dBc/Hz to −135 dBc/Hz, then through the second injection the SSB phase noise drops down to −146 dBc/Hz. 相似文献
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The sensitivity of photonic-delay homodyne phase noise measurement system is improved by using high-linear photodetector and low-phase noise amplifier in this paper. The phase noise model for microwave link is proposed and the sensitivity of photonic-delay based measurement system is analyzed with this theory model. Results show that phase noise sensitivity in this measurement system is −130 dBc/Hz at 1 kHz and −145 dBc/Hz at 10 kHz, and in my knowledge it is the highest sensitivity for photonic-delay homodyne technology without cross correlation. 相似文献