100G Transmission Research Articles

ANN/Random forest based performance monitoring in high-speed short-reach optical interconnections

In this work, we have developed signal quality monitoring approaches in 100/400 Gbit/s short-reach transmission systems, with the application of four advanced modulation formats. In 100G and 400G transmission systems, it is shown that accuracies of 100 % have been achieved in the modulation format identification (MFI), with the use of random forest (RF) and multitask learning-based artificial neural network (MTL-ANN) for the four modulation formats mentioned. Meanwhile, average mean-square errors (MSEs) of the monitored optical signal-to-noise ratio (OSNRs) are less than 0.1 dB. Random forest uses up to 29 adders and 190 comparators, reducing its complexity by two orders of magnitude compared to MTL-ANN.

100G and 200G single carrier transmission over 2880 and 320 km using an InP IQ modulator and Stokes vector receiver.

We demonstrate experimentally the transmission of single carrier 56 Gbaud 16-QAM, 8-QAM and QPSK optically modulated signals over 320, 960 and 2,880 km, respectively, using a fully packaged InP IQ modulator and a Stokes vector direct detection (SV-DD) receiver realized using discrete optics. Results show that by optimizing the carrier-to-signal-power ratio, the total throughput-times-distance product for 16 QAM and QPSK are 71,680 Gbps.km and 322,560 Gbps.km, respectively, at bit error rate (BER) below the hard decision forward error correcting threshold (HD-FEC) of 4.5 × 10-3.

Single-Channel 50G and 100G Discrete Multitone Transmission With 25G VCSEL Technology

This paper explores the feasibility of single-channel 50G and 100G transmission using 25G VCSEL technology. We show through experiments the practicality of 50G transmission through 100 m of OM3 multi-mode fiber. To address the question of whether single-channel 100G transmission is feasible, we show through simulation the needed reduction in relative intensity noise of 25G VCSELs and present a novel modulation technique which offers improved performance over conventional discrete multitone with little additional computational complexity.

Unrepeatered 100G Transmission Over 520.6 km of G.652 Fiber and 556.7 km of G.654 Fiber With Commercial Raman DWDM System and Enhanced ROPA

We report the results of 100G unrepeatered transmission aimed at achieving the longest distance without any inline active elements. The unrepeatered transmission system uses commercial distributed Raman pump modules, enhanced ROPA, and real-time processing coherent 100G transceivers (PM-QPSK) with soft-decision FEC. Two types of ultra-low loss fibers, G.652B and G.654B compliant, are fully characterized and used as span fiber. First, a single 100G channel is successfully transmitted over 520.6 km of G.652B fiber (86.2 dB) in a lab trial. Second, cabled large effective area, ultra-low loss G.654B fiber in a field environment is used as span fiber. A single 100G channel and four 100G channels are transmitted over 556.7 km (90.2 dB) and 523.2 km (84.8 dB), respectively.

Constellation Expansion for Differentially Encoded 100G Transmission

Recent technological progress has enabled the implementation of powerful soft-decision forward error correction codes performing very close to the theoretical Shannon limit. However, recently we showed that, even when the most powerful binary codes are used, a significant potential gain remains unexploited in traditional, coherently detected, non differentially encoded, polarization division multiplexed 100G optical communication systems, when the modulation format is restricted to quadrature phase-shift keying. In this letter, we extend our previous work to the case of differentially encoded systems. Assuming again additive and phase white Gaussian noise, we show that an additional gain of 1-4.5 dB (depending on the amount of phase noise present) is available even when differential transmission is employed, if higher order constellations are used in place of quadrature phase-shift keying. Special care and suitable optimization criteria are required in the choice of the alternative signal constellations since, in contrast with the NDE case, the Euclidean distance is not a significant figure of merit anymore.

A comparison between SSMF and large-A_eff Pure-Silica core fiber for Ultra Long-Haul 100G transmission

We compare the transmission performance of 112-Gb/s POLMUX-QPSK modulation over large-A(eff) Pure-Silica core fiber and SSMF using EDFA-only amplification. The higher nonlinear threshold of the large-A(eff) Pure-Silica core fiber allows for a 55% increase in transmission distance. By using back-propagation an additional 10% increase is observed. In case spans with equal length for both fiber types and two splices per span only would have been used, resulting in a lower span loss for the large-A(eff) Pure-Silica core fiber, the total increase grows to 85%.

Quadrature Duobinary for High-Spectral Efficiency 100G Transmission

This paper proposes and analyzes a quadrature duobinary modulation format with coherent detection for high-spectral efficiency wavelength-division-multiplexing transmission systems at 112 Gb/s per channel. A practical system design of a dual polarization quadrature duobinary (DP-QDB) format with coherent heterodyne detection is analyzed and compared with the DP-differential quadrature phase-shift keying format for feasibility of 112 Gb/s transmission. Using simulation analysis, we show that the relatively narrow spectrum of quadrature duobinary modulation provides an effective practical means for realizing high-spectral efficiency transmission, approaching the theoretical limit of 4 bits/s/Hz, while also providing excellent tolerance to optical filter cascades for a robust optical networking functionality.