Photonics Laboratory, Department of Microtechnology and Nanoscience, Chalmers University of Technology, SE-41296, Göteborg, Sweden.
IT-Instituto de Telecomunicações, 3810-193, Aveiro, Portugal.
Nat Commun. 2018 Apr 23;9(1):1598. doi: 10.1038/s41467-018-04046-6.
Microresonator frequency combs harness the nonlinear Kerr effect in an integrated optical cavity to generate a multitude of phase-locked frequency lines. The line spacing can reach values in the order of 100 GHz, making it an attractive multi-wavelength light source for applications in fiber-optic communications. Depending on the dispersion of the microresonator, different physical dynamics have been observed. A recently discovered comb state corresponds to the formation of mode-locked dark pulses in a normal-dispersion microcavity. Such dark-pulse combs are particularly compelling for advanced coherent communications since they display unusually high power-conversion efficiency. Here, we report the first coherent-transmission experiments using 64-quadrature amplitude modulation encoded onto the frequency lines of a dark-pulse comb. The high conversion efficiency of the comb enables transmitted optical signal-to-noise ratios above 33 dB, while maintaining a laser pump power level compatible with state-of-the-art hybrid silicon lasers.
微谐振器梳状器利用集成光学腔中的非线性克尔效应产生多个锁相同步的频率线。线间距可达到 100GHz 量级，因此成为光纤通信中多波长光源的理想选择。根据微谐振器的色散，已经观察到不同的物理动力学。最近发现的梳状器状态对应于正常色散微腔中形成的锁模暗脉冲。由于这些暗脉冲梳状器具有异常高的功率转换效率，因此对于先进的相干通信特别有吸引力。在这里，我们报告了首次使用暗脉冲梳状器的频率线对 64 正交幅度调制进行相干传输实验。梳状器的高转换效率使传输光信噪比超过 33dB，同时保持与最先进的混合硅激光器兼容的激光泵浦功率水平。
