Li Baiyu, Wei Wei, Han Daming, Xie Weilin, Dong Yi
Opt Express. 2020 Apr 27;28(9):12588-12598. doi: 10.1364/OE.390964.
We propose a phase-stable high-efficiency down-conversion approach for broadband radio frequency signals transmitted from a remote site. A high power coherent optical local oscillator signal is used at the local site to increase the conversion gain and the spurious-free dynamic range (SFDR) at the same time. A sideband optical phase-locked loop ensures the suppression of the phase noise induced by the fiber transmission and the relative frequency drift of the remote and local lasers, which are essential for the signal transmission and the down-conversion. We first experimentally demonstrate the down-conversion of a single frequency signal at 16.45 GHz to a 250 MHz intermediate frequency (IF) signal with 3 dB gain and 103 dB/Hz SFDR after 10 km fiber transmission. Then we show the broadband down-conversion capability by down-converting a 1 GHz wide linear frequency modulated pulse signal centered at 11 GHz to 1 GHz with 3 dB gain. Along with a positive gain, the SFDR of the IF signal down-converted from 5 GHz to 40 GHz has reached 97.6 dB/Hz on average. This approach is suitable for weak broadband remote signal down-conversion with a simple-structured remote end.
我们提出了一种用于从远程站点传输的宽带射频信号的相位稳定高效下变频方法。在本地站点使用高功率相干光本地振荡器信号，以同时提高转换增益和无杂散动态范围（SFDR）。边带光锁相环可确保抑制由光纤传输以及远程和本地激光器的相对频率漂移引起的相位噪声，这对于信号传输和下变频至关重要。我们首先通过实验证明，在10 km光纤传输后，将16.45 GHz的单频信号下变频为250 MHz的中频（IF）信号，增益为3 dB，SFDR为103 dB/Hz。然后，我们通过将以11 GHz为中心的1 GHz宽线性调频脉冲信号下变频为1 GHz，增益为3 dB，展示了宽带下变频能力。除了正增益外，从5 GHz下变频到40 GHz的IF信号的SFDR平均达到了97.6 dB/Hz。这种方法适用于具有简单结构远程端的弱宽带远程信号下变频。
