The implementation of advanced multi-level modulation schemes such as quadrature phase-shift keying (QPSK) in contrast to the conventional on–off keying is crucial to further boost the terahertz (THz) communications speed. Thereby, carrier phase noise reduction in the THz range is one of the key goals that need to be urgently achieved. In this paper, the photonic-based THz sources and the phase noise problem are briefly summarized. Then, a low phase-noise photonic source based on the stimulated Brillouin scattering (SBS) optical fiber cavity is first applied for a 300-GHz-band QPSK wireless communication link. The highest data rate at forward-error-correction limited condition was 15 Gbaud utilizing the SBS-based photonic source with a small transmit power of ~ −36 dBm. Its transmission characteristics are evaluated and compared with the conventional optical frequency comb generator (OFCG)-based source at 5 Gbaud. The proposed SBS-based photonic source has been proven to offer better performances than the OFCG-based source with respect to the phase noise, optical carrier to noise ratio, and bit error rate in communications.

中文翻译：

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使用低相位噪声光子源的 300 GHz 频段无线通信

与传统的开关键控相比，实施先进的多级调制方案，如正交相移键控 (QPSK)，对于进一步提高太赫兹 (THz) 通信速度至关重要。因此，降低太赫兹范围内的载波相位噪声是急需实现的关键目标之一。本文简要总结了基于光子的太赫兹源和相位噪声问题。然后，首先将基于受激布里渊散射（SBS）光纤腔的低相位噪声光子源应用于300GHz频段QPSK无线通信链路。前向纠错受限条件下的最高数据速率为 15 Gbaud，使用基于 SBS 的光子源，发射功率约为 -36 dBm。对其传输特性进行了评估，并与基于 5 Gbaud 的传统光学频率梳发生器 (OFCG) 的源进行了比较。所提出的基于 SBS 的光子源已被证明在相位噪声、光载噪比和通信中的误码率方面比基于 OFCG 的源提供更好的性能。