Transmission of a 73.7 Tb/s (96x3x256-Gb/s) DP-16QAM mode-division-multiplexed signal over 119km of few-mode fiber transmission line incorporating an inline multi mode EDFA and a phase plate based mode (de-)multiplexer is demonstrated. Data-aided 6x6 MIMO digital signal processing was used to demodulate the signal. The total demonstrated net capacity, taking into account 20% of FEC-overhead and 7.5% additional overhead (Ethernet and training sequences), is 57.6 Tb/s, corresponding to a spectral efficiency of 12 bits/s/Hz. ©2012 Optical Society of America

The complexities of common equalizer schemes are analytically analyzed in this paper in terms of complex multiplications per bit. Based on this approach we compare the complexity of mode-division multiplexed digital signal processing algorithms with different numbers of multiplexed modes in terms of modal dispersion and distance. It is found that training symbol based equalizers have significantly lower complexity compared to blind approaches for long-haul transmission. Among the training symbol based schemes, OFDM requires the lowest complexity for crosstalk compensation in a mode-division multiplexed receiver. The main challenge for training symbol based schemes is the additional overhead required to compensate modal crosstalk, which increases the data rate. In order to achieve 2000 km transmission, the effective modal dispersion must therefore be below 6 ps/km when the OFDM specific overhead is limited to 10%. It is concluded that for few mode transmission systems the reduction of modal delay is crucial to enable long-haul performance.

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Transmission of a 73.7 Tb/s (96x3x256-Gb/s) DP-16QAM mode-division-multiplexed signal over 119km of few-mode fiber transmission line incorporating an inline multi mode EDFA and a phase plate based mode (de-)multiplexer is demonstrated. Data-aided 6x6 MIMO digital signal processing was used to demodulate the signal. The total demonstrated net capacity, taking into account 20% of FEC-overhead and 7.5% additional overhead (Ethernet and training sequences), is 57.6 Tb/s, corresponding to a spectral efficiency of 12 bits/s/Hz. ©2012 Optical Society of America

We successfully fabricate three-mode erbium doped fiber with a confined Er(3+) doped ring structure and experimentally characterize the amplifier performance with a view to mode-division multiplexed (MDM) transmission. The differential modal gain was effectively mitigated by controlling the relative thickness of the ring-doped layer in the active fiber and pump launch conditions. A detailed study of the modal gain properties, amplifier performance in a MDM transmission system and inter-modal cross-gain modulation and associated transient effects is presented.

Abstract:We report fabrication of the first low-loss, broadband 37-cell photonic bandgap fiber. Exploiting absence of surface modes and low cross-talk in the fiber we demonstrate mode division multiplexing over three modes with record transmission capacity.OCIS codes: (060.4005) Microstructured fiber; (060.0060) Fiber optics and optical communications.

A carrier phase estimation and compensation algorithm using a digital phase locked loop is proposed which exploits the common-mode impairment from the shared local oscillator at the receiver side in a few-mode fiber transmission system. We verify that the proposed algorithm is more tolerant to phasemismatches than earlier work. The carrier phase estimation (CPE) scheme is evaluated for a 3 × 112 Gbit/s dual polarization quadrature phase shift keying mode division multiplexed transmission over 80 km including an in-line multimode erbium doped fiber amplifier. The digital signal processing computational complexity is reduced in comparison to a traditional CPE stage. In addition, the proposed scheme is shown to perform similarly with respect to the 3.8 × 10 −3 forward error correcting limit optical signal to noise ratio tolerance of the traditional CPE scheme.