400 Gbit/s 256 QAM OFDM Transmission over 720 km with a 14 bit/s/Hz Spectral Efficiency Using an Improved FDE Technique

Omiya, Tatsunori; Yoshida, Masato

doi:10.1364/ofc.2013.oth4e.1

Cited by 4 publications

(4 citation statements)

References 7 publications

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“…With the development of high speed digital-to-analog converter (DAC), coherent optical orthogonal frequency-division multiplexing (CO-OFDM) has attracted a great deal of interest for the transmission systems beyond 100 Gb/s with high spectral efficiencies (SE) [1]- [8]. The straightest way to increase SE is to use high order modulation formats [4]- [14]. Utilization of higher order modulation formats results in higher optical signal-to-noise ratio (OSNR) requirement and an increase of implementation complexity.…”

Section: Introductionmentioning

confidence: 99%

Performance Comparison of DFT-Spread and Pre-Equalization for 8 × 244.2-Gb/s PDM-16QAM-OFDM

2015

J. Lightwave Technol.

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In this paper, we experimentally compared the performance of discrete-Fourier-transform spread (DFT-spread) and pre-equalization in a 244.2-Gb/s polarization-division-multiplexed 16-ary quadrature amplitude-modulation orthogonal frequencydivision multiplexing (PDM-16QAM-OFDM) transmission system . The pre-equalization is effective to overcome the high-frequency power attenuation in the channel. However, the acquisition of static channel response for pre-equalization is really complicated and the peak-to-average power ratio (PAPR) of the signal after preequalization even becomes a little higher. The DFT-spread can be applied to simultaneously resist high-frequency power attenuation and reduce the PAPR of OFDM signal. The experimental results also show that one band DFT-spread demonstrates the best narrow optical filtering tolerance. The transmission distance for 8 × 244.2-Gb/s wavelength-division-multiplexing (WDM) PDM-16QAM-OFDM at the soft-decision forward-error correction threshold of 2.4 × 10 −2 is 2 × 420 km based on preequalization, while extended to over 3 × 420 km based on one band DFT-spread, which well illustrates one band DFT-spread is more efficient for high-bandwidth coherent WDM-OFDM system.Index Terms-Discrete-fourier-transform spread (DFT-spread), narrow optical filtering tolerance, orthogonal frequency division multiplexing (OFDM), pre-equalization.

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Section: Introductionmentioning

confidence: 99%

Performance Comparison of DFT-Spread and Pre-Equalization for 8 × 244.2-Gb/s PDM-16QAM-OFDM

2015

J. Lightwave Technol.

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“…To meet the bandwidth demand, much research has been focused on standard single-mode fiber (SSMF) to improve the spectral efficiency (SE) by means of polarization-division multiplexing [1], orthogonal-frequency division multiplexing (OFDM) [2], and multilevel modulation [3]. However, SSMF is approaching its so-called nonlinear Shannon capacity limit [4], [5].…”

Section: Introductionmentioning

confidence: 99%

Fabrication of a Low-Loss Fused Fiber Spatial-Mode Coupler for Few-Mode Transmission

Liu

Jia

Chen

et al. 2013

IEEE Photon. Technol. Lett.

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Spatial-mode couplers (SMCs) are critical devices for mode-division-multiplexed (MDM) systems. In this letter, we report a low-loss symmetric SMC fabricated with customdesigned two-mode fiber and commercially available standard fused biconical taper station. Sophisticated hydrofluoric etching or pre-pulling on the fiber sample is not needed for fabrication. We characterize the performance of the fabricated SMC, which shows a low loss of 1.1-2 dB and high modal extinction ratio of ≥20 dB for a broad wavelength range from 1539 to 1555 nm. We demonstrate transmission of 69.2-Gb/s LP 01 /LP 11 dual-mode MDM coherent optical orthogonal-frequency division multiplexing signal over 4.5-km two-mode fiber using the fabricated SMC as mode multiplexer. The signal is successfully received at low (0.1/0.5 dB) optical signal-to-noise ratio penalty, and the estimated channel matrix confirms that there is very low modal crosstalk in both the SMC and the fiber.

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“…Self-homodyne coherent technology [13][14][15][16][17][18][19][20][21][22] where the LO laser is transmitted together with the signal relaxes the requirements for DSP since eliminates the need for frequency offset compensation between transmitter laser and LO. Yet, for single-carrier modulation this technology sacrifices one of the two orthogonal polarizations of the fiber to fit an optical carrier that halves transmission capacity.…”

mentioning

confidence: 99%

“…Yet, for single-carrier modulation this technology sacrifices one of the two orthogonal polarizations of the fiber to fit an optical carrier that halves transmission capacity. For multicarrier schemes such as self-coherent optical orthogonal frequencydivision multiplexing (Self-CO-OFDM) [14,15,19,20,22], it typically requires a large carrier guardband (i.e. frequency gap that discards many OFDM middle subcarriers) for filtering-out the carrier that significantly limits signal capacity.…”

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confidence: 99%

Chip-based Brillouin processing for carrier recovery in self-coherent optical communications

Choudhary

Mägi

Marpaung

et al. 2018

Optica

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Modern fiber-optic coherent communications employ advanced, spectrally-efficient modulation formats that require sophisticated narrow linewidth local oscillators (LOs) and complex digital signal processing (DSP). Self-coherent optical orthogonal frequency-division multiplexing (Self-CO-OFDM) is a modern technology that retrieves the frequency and phase information from the extracted carrier without employing a LO or additional DSP. However, a wide guardband is typically required to easily filter out the optical carrier at the receiver, thus discarding many OFDM middle subcarriers that limits the system data rate. Here, we establish an optical technique for carrier recovery harnessing large-gain stimulated Brillouin scattering (SBS) on a photonic chip for up to 116.82 Gbit⋅s -1 Self-CO-OFDM signals, without requiring a separate LO. The narrow SBS linewidth allows for a record-breaking small carrier guardband of ~265 MHz in Self-CO-OFDM, resulting in higher capacity than benchmark self-coherent multi-carrier schemes. Chip-based SBS-self-coherent technology reveals comparable performance to state-of-the-art coherent optical receivers while relaxing the requirements of the DSP. In contrast to SBS processing on-fiber, our solution provides phase and polarization stability. Our demonstration develops a low-noise and frequency-preserving filter that synchronously regenerates a low-power narrowband optical tone, which could relax the requirements on very-high-order modulation signaling for future communication networks. The proposed hybrid carrier filtering-and-regeneration technique could be useful in long-baseline interferometry for precision optical timing or reconstructing a reference tone for quantum-state measurements.

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400 Gbit/s 256 QAM OFDM Transmission over 720 km with a 14 bit/s/Hz Spectral Efficiency Using an Improved FDE Technique

Abstract: We demonstrate 400 Gbit/s PDM-256 QAM-OFDM transmission with 14 bit/s/Hz spectral efficiency by employing an improved FDE technique that extended the transmission distance to 720 km and achieved an SE-distance product of 10,080 km⋅bit/s/Hz.

Cited by 4 publications

References 7 publications

Performance Comparison of DFT-Spread and Pre-Equalization for 8 × 244.2-Gb/s PDM-16QAM-OFDM

Performance Comparison of DFT-Spread and Pre-Equalization for 8 × 244.2-Gb/s PDM-16QAM-OFDM

Fabrication of a Low-Loss Fused Fiber Spatial-Mode Coupler for Few-Mode Transmission

Chip-based Brillouin processing for carrier recovery in self-coherent optical communications

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