We report a novel photonic scheme to generate binary phase-coded microwave signals by using two cascaded phase modulators (PMs) based on a Fourier domain mode-locked (FDML) optoelectronic oscillator (OEO). The first PM is driven by a series of electrical coding signals to modulate the phase of the optical carrier. The second PM is a construction of the FDML OEO, which realizes phase-modulation to intensity-modulation conversion together with a phase-shifted fiber Bragg grating. Phase-coded microwave signals can be generated when the period of the electrical coding signal matches with the round-trip time of the OEO. A $\boldsymbol {\pi }$ phase shift of the phase-coded microwave signals can be achieved by properly adjusting the level of the electrical coding signal. The key point of our work is that phase-coded microwave signals can be generated directly from the FDML OEO cavity. Besides, the proposed system has great reconfigurability in terms of center frequency and bit rate. Our scheme is theoretically analyzed and experimentally verified. Phase-coded microwave signals with a bit rate of 420 Mb/s and center frequency of 9.3 GHz, as well as with a bit rate of 2 Gb/s and center frequency of 12.7 GHz are successfully generated in the experiment.

中文翻译：

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基于傅里叶域锁模的相位编码微波信号的光子产生

我们报告了一种新颖的光子方案，通过使用基于傅立叶域锁模（FDML）光电振荡器（OEO）的两个级联相位调制器（PM）来生成二进制相位编码的微波信号。第一PM由一系列电编码信号驱动，以调制光学载波的相位。第二个PM是FDML OEO的构造，它与相移光纤布拉格光栅一起实现了从相位调制到强度调制的转换。当电编码信号的周期与OEO的往返时间匹配时，可以生成相位编码的微波信号。一个 $ \ boldsymbol {\ pi} $ 可以通过适当地调整电编码信号的电平来实现相编码的微波信号的相移。我们工作的重点是可以直接从FDML OEO腔中产生相位编码的微波信号。此外，所提出的系统在中心频率和比特率方面具有很大的可重构性。我们的方案经过理论分析和实验验证。在实验中成功生成了比特率为420 Mb / s，中心频率为9.3 GHz，比特率为2 Gb / s，中心频率为12.7 GHz的相位编码微波信号。