Li Lu, Patki Pallavi G, Kwon Young B, Stelmakh Veronika, Campbell Brandon D, Annamalai Muthiah, Lakoba Taras I, Vasilyev Michael
Department of Electrical Engineering, University of Texas at Arlington, Arlington, TX, 76019, USA.
TE SubCom, Eatontown, NJ, 07724, USA.
Nat Commun. 2017 Oct 12;8(1):884. doi: 10.1038/s41467-017-00874-0.
One of the main reasons why nonlinear-optical signal processing (regeneration, logic, etc.) has not yet become a practical alternative to electronic processing is that the all-optical elements with nonlinear input-output relationship have remained inherently single-channel devices (just like their electronic counterparts) and, hence, cannot fully utilise the parallel processing potential of optical fibres and amplifiers. The nonlinear input-output transfer function requires strong optical nonlinearity, e.g. self-phase modulation, which, for fundamental reasons, is always accompanied by cross-phase modulation and four-wave mixing. In processing multiple wavelength-division-multiplexing channels, large cross-phase modulation and four-wave mixing crosstalks among the channels destroy signal quality. Here we describe a solution to this problem: an optical signal processor employing a group-delay-managed nonlinear medium where strong self-phase modulation is achieved without such nonlinear crosstalk. We demonstrate, for the first time to our knowledge, simultaneous all-optical regeneration of up to 16 wavelength-division-multiplexing channels by one device. This multi-channel concept can be extended to other nonlinear-optical processing schemes.Nonlinear optical processing devices are not yet fully practical as they are single channel. Here the authors demonstrate all-optical regeneration of up to 16 channels by one device, employing a group-delay-managed nonlinear medium where strong self-phase modulation is achieved without nonlinear inter-channel crosstalk.
非线性光学信号处理（再生、逻辑等）尚未成为电子处理的一种实用替代方案，其主要原因之一是具有非线性输入输出关系的全光元件本质上仍是单通道器件（就像它们的电子对应物一样），因此无法充分利用光纤和放大器的并行处理潜力。非线性输入输出传递函数需要很强的光学非线性，例如自相位调制，而由于基本原因，自相位调制总是伴随着交叉相位调制和四波混频。在处理多个波分复用通道时，通道之间大的交叉相位调制和四波混频串扰会破坏信号质量。在此，我们描述了这个问题的一种解决方案：一种采用群时延管理非线性介质的光信号处理器，在这种介质中可以实现很强的自相位调制而不会产生这种非线性串扰。据我们所知，我们首次展示了一个器件能同时对多达16个波分复用通道进行全光再生。这种多通道概念可以扩展到其他非线性光学处理方案。非线性光学处理设备由于是单通道的，所以尚未完全实用。在此，作者展示了一个器件能通过采用群时延管理非线性介质对多达16个通道进行全光再生，在这种介质中可以实现很强的自相位调制而不会产生通道间非线性串扰。
