We present a novel optical transmission system to experimentally demonstrate the possibility of mode division multiplexing. Its key components are mode multiplexer and demultiplexer based on a programmable liquid crystal on silicon panel, a prototype few-mode fiber, and a 4×4 multiple input multiple output algorithm processing the information of two polarization diversity coherent receivers. Using this system, we transmit two 100 Gb/s PDM-QPSK data streams modulated on two different modes of the prototype few-mode fiber. After 40 km, we obtain Q(2)-factors about 1 dB above the limit for forward error correction.
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http://dx.doi.org/10.1364/OE.19.016593 | DOI Listing |
For weakly coupled mode-division multiplexed (MDM) transmission systems, we design and implement optical coherent receiver prototypes with real-time multiple-input multiple-output (MIMO) digital signal processing to equalize two degenerate linearly polarized modes with dual polarization. Using field programmable gate array circuits, we implement real-value 8 × 2 MIMO adaptive equalization with externally separated phase compensators based on the least mean square algorithm, which enables not only training equalization but also fast carrier-phase tracking. With the optical coherent MIMO receiver prototype, we demonstrate real-time weakly coupled 10 × MDM wavelength-division multiplexed dual-polarization quadrature phase shift keying transmission over 48-km few-mode fibers.
View Article and Find Full Text PDFMultiple-input-multiple-output digital signal processing (DSP) has become a severe bottleneck for mode division multiplexing (MDM) because of its huge computational complexity. In this paper, we propose a novel scheme for real-time DSP-free intensity-modulation/direct-detection (IM/DD) MDM transmission, in which the transmission few-mode fiber (FMF) is characterized by multiple-ring-core structure to suppress modal crosstalk among each LP mode, while each pair of non-circularly-symmetric degenerate modes is simultaneously demultiplexed by a degenerate-mode-selective fiber coupler for DSP-free reception. Based on a 10 km ultralow-modal-crosstalk double-ring-core FMF and a pair of all-fiber 4-LP-mode MUX/DEMUX, we demonstrate the first IM/DD MDM prototype system using commercial single-mode (SM) 10 Gbps SFP + modules and 4K video transceivers without any hardware modifications.
View Article and Find Full Text PDFIn recent years, to enlarge the single-mode fibers (SMFs) transmission capacity, researchers focused on the dimension of space, which is a new degree of freedom that is being considered for optical fiber communication beyond WDM. Space-division multiplexing (SDM), including mode-division multiplexing (MDM) using multimode fibers (MMFs) or few-mode fibers (FMFs), and core multiplexing using multicore fibers (MCFs), has attracted much recent attention. In an SDM system, high-density spatial channels are tightly packed into a single fiber, thus making crosstalk among cores or modes a critical challenge due to fiber imperfections, bending, and twisting.
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August 2011
Alcatel-Lucent Bell Labs, centre de Villarceaux, route de Villejust, 91620 Nozay, France.
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