Robust multidimensional optical modulation based on hybrid subcarrier/amplitude/phase/dual polarization for wavelength-division multiplexing systems

Abstract

Here, we propose a novel scheme based on advanced digital modulation techniques in optical communications to achieve a single-channel transmission rate above 100 Gb/s. We utilize a hybrid scheme amplitude/phase/frequency/dual polarization, combined with multidimensional dual lattice and a low-density parity-check-coded modulation. The Stokes parameters are applied to the proposed scheme to map the four-dimensional classical polarization I_X, Q_X, I_Y, and Q_Y in a three-dimensional space. In addition, the packing theory is applied to the bit interleaving process in the proposed system. Three wavelengths are packaged before being transmitted over a wavelength-division multiplexing optical channel. This modulation process uses symmetrical geometric shapes, such as a hypercube or a polyhedron, based on the molecular links theory using a grouping of 12 and 13/15 bits for the cubic and spherical lattices, respectively. The proposed technique is evaluated in the context of long-distance communications over distances up to 100km. The bit error rate (BER) results showed that the optical signal-to-noise ratio was approximately 4dB over 50km. In addition, the power spectral efficiency was found to be three lambdas, which is considered a good performance considering the effects of distance and the non-linear effects influencing the number of lambdas. Also, we use an optical time-division multiplexing scheme (OTDM) to achieve a transmission rate beyond 1Tbit/s, where the speed effect is evaluated, considering that the power spectral efficiency is degraded.