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 techniques of digital modulation 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 IX, QX, IY, QY in a three-dimensional space. In addition, in the proposed system, the packing theory is applied to the bit interleaver process. Three wavelengths are packaged before being transmitted over a wavelength-division multiplexing optical channel. This modulation process is carried out using 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 a distance of 50km. In addition, the power spectral efficiency was found to be 3 lambdas, which is considered 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) in order to achieve a transmission rate beyond 1Tbit/s, where the speed effect is evaluated, taking into consideration that the power spectral efficiency is degraded.

Keywords

• Coherent Optical Communications
• Polyhedron
• Hypercube
• Multidimensional Modulations
• Stokes parameters
• Poincare sphere