Capacity improvement of TWDM-PONs exploiting the 16-qam technique for downstream side with a nonlinearity effect study for upstream DML

• Published in: Journal of Optical Communications and Networking
• Main Authors: Bindhaiq, Salem, Zulkifli, Nadiatulhuda, Supa'at, Abu Sahmah M., Shaddad, Redhwan Q.
• Format: Article in Journal/Newspaper
• Language: unknown
• Published: Institute of Electrical and Electronics Engineers Inc. 2015
• Subjects: TK Electrical engineering. Electronics Nuclear engineering; DML
• Online Access: http://eprints.utm.my/57994/; https://doi.org/10.1364/JOCN.7.001018

Currently, the main goal of developing time-wavelength-division multiplexing passive optical networks (TWDM-PONs) is to acquire capacity improvement in a scalable and cost-effective manner. In response to the challenge, this paper demonstrates a full-system TWDM-PON through physical layer simulation that provides 56 Gb/s downstream and 40 Gb/s upstream bandwidths. We propose a simple and cost-effective scheme to improve the capacity of the downstream signal by utilizing highly spectrally efficient 16 quadrature amplitude modulation (QAM) with 20 GHz radio-over-fiber signal distribution using a single sideband signal that is generated by an optical dual-arm modulator. In addition, we study the effect of nonlinearity on a directly modulated laser (DML) as the upstream laser of an optical network unit. The outcomes obtained revealed good transmission quality in both directions, where bit error ratios of 10-6 and 10-5 are obtained for the downstream and upstream transmissions, respectively. This leads to the ability to support up to 128 users over 40 km of single-mode fiber.