Discrete multi-tone (DMT) technology is an attractive modulation technology for short-reach application due to its high
spectral efficiency and simple configuration. In this paper, we first explain the features of DMT technology then discuss
the impact of fiber dispersion and chirp on the frequency responses of the DMT signal and the importance in the
relationship between chirp and the optical transmission band. Next, we explain our experiments of 100-Gb/s DMT
transmission of 10 km in the O-band using directly modulated lasers for low-cost application. In an inter-datacenter
network of more than several tens of kilometers, fiber dispersion mainly limits system performance. We also discuss our
experiment of 100-Gb/s DMT transmission up to 100 km in the C-band without a dispersion compensator by using
vestigial sideband spectrum shaping and nonlinear compensation.
Proc. SPIE. 9388, Optical Metro Networks and Short-Haul Systems VII
KEYWORDS: Signal to noise ratio, Transmitters, Modulation, Numerical simulations, Single mode fibers, Data conversion, Forward error correction, Multiplexers, Orthogonal frequency division multiplexing, Laser sintering
Discrete multi-tone (DMT) technology is an attractive modulation technique for short reach optical transmission system. One of the main factors that limit system performance is fiber dispersion, which is strongly influenced by the chirp characteristics of transmitters. We investigated the fiber dispersion impairment in a 400GbE (4 × 116.1-Gb/s) DMT system on LAN-WDM grid for reach enhancement up to 40 km through experiments and numerical simulations.
Effective utilization of fiber capacity in optical communication networks is required to keep up with the increasing traffic demand. Precise optical frequency allocation among carriers is essential for improving the spectral efficiency to utilize the limited spectral resource. In this paper, we show a distributed optical multiplexing scheme, in which data signals are sequentially multiplexed by frequency-division multiplexing on a single-wavelength optical carrier using fiber frequency conversion with locally provided optical subcarrier signals. The scheme achieves dense packing of distributed multi-channel signals with precise frequency allocation using free-running lasers. Using the scheme we demonstrate a precise multiplexing of coherent-optical orthogonal frequency-division multiplexing and Nyquist wavelength-division multiplexing.