Fiber Nonlinearity Compensation

Google Tech Talk May 31, 2013 (more info below) ABSTRACT With the ever-increasing demand for bandwidth, it is critical that we increase the capacity of optical networks. Coherent systems are now able to compensate for linear impairments such as CD and PMD. However, fiber nonlinearity limits the maximum power that systems can operate at; higher optical signal-to-noise ratios (OSNR) cannot be achieved by increasing the power. The capacity of optical links can be significantly increased by fiber nonlinearity compensation. The majority of recent nonlinearity compensation research has focused on using digital techniques such as backpropagation (BP). The computational power required for BP has so far prohibited it from being implemented using real-time digital signal processing (DSP). Alternatively, optical techniques can also be used to improve the nonlinearity-limited performance of optical systems. For example optical phase conjugation (OPC) can be performed near the mid-point of the link so the fiber nonlinearity products generated in the second half of the link mitigate the fiber nonlinearity products generated in the first half. There have also been end-link optical techniques proposed. Optical techniques have the advantage of being more scalable to multi-wavelength systems but require modifications to the external plant. In this presentation, an overview of both digital and optical nonlinearity compensation will be presented. The advantages and limitations of each method will be discussed for the different optical network topologies, including point-to-point links, mesh optical networks and future super-channel applications. SPEAKER INFO Liang Bangyuan Du was born in Shenyang, China in 1985. He received the B.Eng. (with first class Hons.) and Ph.D. degrees in electrical and computer systems engineering from Monash University, Melbourne, Vic., Australia, in 2007 and 2012, respectively. His research interests include fiber nonlinearity mitigation in long-haul systems, advanced modulation formats and multi-carrier transmission, including orthogonal frequency division multiplexing (OFDM). He is currently working at Monash University as a Research Fellow. Dr. Du received Corning Outstanding Student Paper Award and the Optical Fiber Communication Conference in 2011 for his work on cross-phase modulation compensation. In 2012, he was awarded the Best Student Paper Award in the Transmission Systems subcommittee at the OptoElectronics and communications conference for work involving mid-span spectral inversion for optical OFDM. He has authored or co-authored over 50 journal and conference papers, including four postdeadlines.