A Pulse Shaping Based Optical Transmission System of 128QAM for DWDM with N × 904 Gbps

Abstract

In this paper, we propose an optical transmission system of 128 quadrature amplitude modulation for dense wavelength division multiplexing. In such a system, Gaussian optical filtering is used to get an appropriate photonic carrier. Theoretical analysis and simulation computation show that the modulated multi-carrier photonic signals with the wavelength spacing of 0.7 nm can transmit for over 80 km with the standard single mode fiber. Using digital signal processing algorithms to compensate the transmission impairments, the transmission rate of the single-carrier photonic signal can reach up to 904 Gbps and the spectral efficiency of the transmission can reach up to 10.33 bps/Hz. When this technology is applied to a dense wavelength division multiplexing system with N channels, the huge message capacity of N × 904 Gbps can be realized. Furthermore, we find that the bit error rate and the error vector magnitude are similarly influenced by the optical signal-to-noise ratio and the bandwidth of the Gaussian optical filter. The influence presents mostly a synchronization trend with the change of the optical signal-to-noise ratio and the bandwidth of Gaussian optical filter.

Special Issue on Light Communications: Latest Advances and Prospects

“…Wang, et al [23] have presented a broadband planar lightwave circuit splitter with a variable splitting ratio that is designed for signal distribution in passive optical network. Li, et al [24] have reported pulse-shaping-based optical transmission for a 128-QAM (quadrature amplitude modulation) DWDM (dense wavelength division multiplexing) system that has a potential capacity equal to 904 Gbps per channel. Finally, Abd El-Mottaleb, et al [25] have presented the analysis and evaluation of a spectral amplitude coding optical code-division multiple-access system with the enhanced double-weight codes as signature codes.…”

Comparative Analysis for Different Digital Modulation Techniques

“…Its unit is bit/sec/Hz and can be mathematically expressed as [12]: (11) From equation 11, the ratio (C/B) is the bandwidth efficiency and the ratio (Eb/No) is the power efficiency or SNR per bit. Table 3 shows how the bandwidth efficiency can be approximately expressed in each model of the studied digital modulation schemes, where M-ary signalling M = 2, 4, 8, 16, 32, 64, 128... and so on [13], [14]. Table 3.…”

Comparison of coherent optical transmission systems performance by DP-QAM levels

“…Also COTS is compatible with Multi level modulation format and has better spectral efficiency. Due to these advantages, COTS is employed in DWDM systems [8].…”