We summarize several novel schemes to generate multi-level modulation formats for high capacity transmission system with high spectral efficiency. We show that multi-level 8QAM, 16QAM, 32QAM, and 64QAM (QAM: quatlrature amplitude modulation) optical signals can be generated by commercial optical and electrical devices. Employing these multilevel modulation formats, we have realized PDM-8QAM (PDM: polarization division multiplexing) 32 Tb/s and PDM-36QAM 64-Tb/s signals transmission over 580- and 320-km fibers, respectively.
© 2010 Chinese Optics Letters
(190.4370) Nonlinear optics : Nonlinear optics, fibers
(250.4480) Optoelectronics : Optical amplifiers
(250.5530) Optoelectronics : Pulse propagation and temporal solitons
(250.0040) Optoelectronics : Detectors
(250.4110) Optoelectronics : Modulators
Jianjun Yu and Xiang Zhou, "Novel schemes to generate multi-level modulation formats for ultra-capacity coherent detection transmission systems (Invited Paper)," Chin. Opt. Lett. 8, 823-830 (2010)