Optical Phase Conjugation in a Silicon Waveguide With Lateral p-i-n Diode for Nonlinearity Compensation
Optical Phase Conjugation in a Silicon Waveguide With Lateral p-i-n Diode for Nonlinearity Compensation
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DOI：
10.1109/jlt.2018.2873684
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发表时间：
2019-01-15
影响因子：
4.7
通讯作者：
Galili, Michael
中科院分区：
文献类型：
--
作者：
Da Ros, Francesco;Gajda, Andrzej;Galili, Michael
在线光相位共轭是一种通过非线性补偿来提高接收信号质量的众所周知的技术。能够在可集成在硅芯片上的厘米级高度非线性器件中实现共轭，可能会在占地面积小、与线性信号处理功能协同集成以及更低功耗方面带来几个好处。在这里，我们将重点放在硅波导上，通过四波混频来实现光学相位共轭。通过使用沿波导的横向p-i-n二极管，解决了由于存在非线性损耗而带来的转换效率方面的挑战。当二极管反向偏置时，可以通过减少自由载流子吸收来有效地提高转换效率。因此，可以实现波分复用(WDM)信号的低损耗转换，并且在经过644千米的色散补偿传输之后，在5-WDM信道16-QAM传输系统中，通过光学相位共轭，所产生的空闲信号的高质量是展示1dBQ因数改善的关键。该性能改进使得所有传输信道的性能都好于硬判决前向纠错阈值。
In-line optical phase conjugation is a well-known technique to enhance the received signal quality through non-linearity compensation. Being able to implement the conjugation in cm-scale highly nonlinear devices, which can be integrated on a silicon chip, could potentially lead to several benefits in terms of small footprint and cointegration with linear signal processing functionalities, as well as lower power consumption. Here, we focus on silicon waveguides to implement the optical phase conjugation through four-wave mixing. The challenges in terms of conversion efficiency imposed by the presence of nonlinear loss are tackled by using a lateral p-i-n diode along the waveguide. When the diode is reverse biased, the conversion efficiency can be effectively enhanced by the decrease in free-carrier absorption. Low-penalty conversion can therefore be achieved for wavelength-division multiplexing (WDM) signals and the high quality of the generated idlers is critical in demonstrating a 1-dB Q-factor improvement through optical phase conjugation in a 5-WDM channel 16-QAM transmission system after 644 km of dispersion-compensated transmission. The performance improvement enables a performance better than the hard-decision forward error correction threshold for all the transmitted channels.