Dual-LP_11 mode 4x4 MIMO-OFDM transmission over a two-mode fiber

Abstract

We report successful transmission of dual-LP(11) mode (LP(11a) and LP(11b)), dual polarization coherent optical orthogonal frequency-division multiplexing (CO-OFDM) signals over two-mode fibers (TMF) using all-fiber mode converters. Mode converters based on mechanically induced long-period grating with better than 20 dB extinction ratios are realized and used for interfacing single-mode fiber transmitter and receivers to the TMF. We demonstrate that by using 4×4 MIMO-OFDM processing, the random coupling of the two LP(11) spatial modes can be successfully tracked and equalized with a one-tap frequency-domain equalizer. We achieve successful transmission of 35.3 Gb/s over 26-km two-mode fiber with less than 3 dB penalty.

WDM-compatible mode-division multiplexing on a silicon chip

“…In contrast, fibre communications are increasingly targeting multimode operation in conjunction with WDM to further scale the communication bandwidth transmitted per fibre 3 . Multimode communications in fibres have been demonstrated with space-division multiplexing in multi-core fibres [4][5][6][7][8] or mode-division multiplexing (MDM) in few-mode fibres [9][10][11][12][13][14][15][16][17] and have exploited each spatial mode as an independent channel. It is similarly of interest to attempt to incorporate the spatial-mode-parallelism degree of freedom into complex photonic-integrated circuits to introduce additional functionality and provide potential performance gains.…”

Performance of Direct-Detection Mode-Group-Division Multiplexing Using Fused Fiber Couplers

“…Another possibility for the implementation of the whole multiplexer/demultiplexer is to use a single few-core coupler for simultaneously processing all the groups of modes, instead of the cascades of two-and three-core couplers described above. This approach has been reported for the first time in [14] regarding a four-core coupler that works simultaneously with LP 11 and LP 21 groups of modes, where its performance is evaluated for the presence of only a single mode group. A more complete analysis of its multiplexing performance would require modeling the intermodal crosstalk associated with the presence of all the mode groups propagating through the FMF, which has not been attempted before.…”

“…This approach includes converters based on mechanically induced long-period fiber gratings [11], and recently proposed few-core mode-selective couplers [12][13][14], which may be fabricated in photonic-crystal technology. Photonic lanterns offer another promising approach based on lossless adiabatic tapers that merge a set of SMFs into a set of MMF modes.…”

Serial branching mode multi/demultiplexer for homogeneous multi-core fibers

“…The orthogonal eigenmodes in a fiber are utilized as independent transmission channels in the MDM scheme. Thus far, to realize the MDM transmission, several novel optical fibers have been proposed such as the few-mode fiber (FMF) [2,3,4] which supports several modes by expanding the core diameter and strongly coupled multicore fiber (MCF) [5,6] which utilizes coupled modes supported in coupled single mode cores as independent transmission channels. On the other hand, weakly coupled MCFs have been proposed and demonstrated [7,8] to reduce the difference of group delay between coupled modes.…”