Ngo Thi Thu Trang, Nguyen Duc Nhan, Bui Trung Hieu

Main Article Content

Abstract

In direct-detection optical OFDM system, the nonlinear impairment is the key factor that limits the system performance. The back-propagation techniques in digital and optical domains have been proposed to compensate the nonlinear effects, however they can be unsuitable for long-range passive optical networks (LR-PONs) due to their implementation at receiver. In this study, we propose an optical back propagation (OBP) approach for compensation of the nonlinear and dispersion distortions in direct-detection optical OFDM system. The proposed OBP using split-step Fourier method is implemented at transmitter that is suitable for high-rate OFDM-based LR-PONs applications. In this OBP, the fiber Bragg grating (FBG) is used as a step for dispersion compensation and the high-nonlinear fiber (HNLF) with a short length is used as a step for nonlinear compensation. The performance improvement based on our proposed approach has been demonstrated via Monte-Carlo simulations of the 100 Gbit/s direct-detection optical OFDM system with 80 km of standard single mode fiber link. The influence of optical conjugation process and launching conditions has been investigated. The obtained results show that the proposed OBP can improve remarkably the performance of system with the launched power range from -2 dBm to 6 dBm.

Keywords: OFDM, direct detection, optical transmission, nonlinear compensation, optical back propagation.

References

[1] N. Cvijetic, OFDM for Next-Generation Optical Access Networks, J. Light. Technol., 30 (2012) 384-398.
[2] V. Shukla, D.R. Stauffer, et al., Technology options for 400G implementation, O.I. Forum, Vol. OIF-Tech-Options-400G-01.1 (2015).
[3] Y. Yang, Z. Zeng, S. Feng, C. Guo, A simple OFDM scheme for VLC systems based on μ-law mapping, IEEE Photonics Tech. Letters, 28 (2015) 641-644.
[4] N.T. Trang, B.T. Hieu, N. Nhan, Performance improvement of IM-DD Optical OFDM system using A-law companding transform, Proceedings of The International Conference on Advanced Technologies for Communications (ATC), (2018) 203-207. https://doi.org/10.1109/ATC.2018.8587477
[5] C.Y. Lin, M. Holtmannspoetter, M.R. Asif, B. Schmauss, Compensation of transmission impairments by digital backwark propagation for different link designs, Proceedings 36th European Conf. Optical Comm. (ECOC), (2010). https://doi.org/10.1109/ECOC.2010.5621413
[6] T.T. Binh, N.D. Nhan, N.T. Trang, A Comparison for Improving The Performance of Two-Stage Optical Phase Conjugation Using The Third-Order Nonlinearity, Proceedings of The 4th NAFOSTED Conference on Information and Computer Science (NICS), (2017) 168-173. https://doi.org/10.1109/NAFOSTED.2017.8108058
[7] S. Kumar, D. Yang, Optical backpropagation for fiber-optic communications using highly nonlinear fibers, Optics Letters, 36 (2011) 1038-1040.
[8] X. Liang, S. Kumar, Optical backpropagation for compensating nonlinear impairments in fiber optic links with ROADMs, Optics Express, 24 (2016) 22682-22692.
[9] J. Shao, S. Kumar, Optical backpropagation for fiber-optic communications using optical phase conjugation at the receiver, Optics Letters, 37 (2012) 3012-3014.
[10] X. Liang, S. Kumar, Optical back propagation for fiber optic networks with hybrid EDFA Raman amplification, Optics Express, 25 (2017) 5031-5043.
[11] G.P. Agrawal, Nonlinear Fiber Optics, 4th ed., Academic Press, 2007.
[12] A.J. Lowery, S. Wang, M. Premaratne, Calculation of power limit due to fiber nonlinearity in optical OFDM systems, Optics Express, 15 (2007) 13282-13287.