The M-ary support vector machine (SVM) is introduced as a nonparameter nonlinear phase noise (NLPN) mitigation approach for the coherent optical systems. The NLPN tolerance of the system can be improved by using the M-ary SVM to conduct nonlinear detection. In this scheme, SVMs with different classification strategies are utilized to execute binary classification for signals impaired by fiber NLPN. Since the separating hyperplane of each SVM is constructed by training data, this scheme is independent from the knowledge of the transmission link. In numerical simulation, the M-ary SVM performs better than the method of amplitude-dependent phase rotation at the transmitter and receiver, as well as the maximum likelihood detection with back rotation.Index Terms: Nonlinear phase noise, quadratic amplitude modulation (QAM), support vector machine (SVM), M-ary SVM.

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A support vector machine (SVM)-based data detection is proposed for coherent optical fiber amplitude phase-shift keying (APSK) communication systems where the nonlinear phase noise is the main system impairment. The performances of the detection with SVMs are investigated for three different 16-APSK modulation formats. In addition, three transmission scenarios with dispersion being considered or not are adopted to simulate and analyze the performances. Compared with the traditional two-stage maximum-likelihood detection, the SVM conducts detection without the need to know the information of transmission link, and it gains a relatively large improvement in the nonlinear system tolerance, particularly in the high nonlinear regime. Compared with quadrature amplitude modulation (QAM), the 16-APSK system can increase the nonlinear system tolerance by 4.88 dB at BER ¼ 1E À 3.Index Terms: Support vector machine (SVM), amplitude phase-shift keying (APSK), nonlinear phase noise (NLPN).

A series of N-heterocyclic carbene-sulfonate (NHC-sulfonate) p-cymene ruthenium complexes (2a-2d) were synthesized in high yields from the reactions of NHC-sulfonate ligands with Ag 2 O and [(p-cymene)RuCl 2 ] 2 . All of the complexes were characterized fully by 1 H and 13 C NMR spectroscopy, high-resolution mass spectrometry, and elemental analysis. The molecular structures of 2b and 2d were determined by single-crystal X-ray diffraction analysis. Upon activation with Et 2 AlCl, the ruthenium complexes 2a-2d showed