Four-dimensional (4-D) set-partitioning quadrature amplitude modulation (4-D SP-QAM) has emerged as an interesting option for cost- and resource-efficient realization of bandwidth variable ...transceivers in elastic optical networks. In this invited paper, we review the principles for generation of 4-D SP-QAM signals, and describe options for forward error correction coding of 4-D SP-QAM signals and for realization of the digital signal processing in the coherent receiver. Furthermore, we report on the experimental realization of 4-D 512-ary and 2048-ary SP-QAM signals at a symbol rate of 28 GBd and investigate their performance in a Nyquist-WDM scenario. In transmission experiments over standard single-mode fiber, we compare the reach and spectral efficiency of five-carrier Nyquist-WDM signals modulated by various 4-D SP-QAM formats and polarization-division multiplexed (PDM) QAM formats. Of these modulation formats, the one with the lowest spectral efficiency is 128-ary SP-QAM encoding 7 bits/4-D symbol and the one with the highest spectral efficiency is PDM-64QAM encoding 12 bits/4-D symbol. By switching the modulation format, the spectral efficiency can be optimized for a specific reach with a granularity of 0.56 bit/s/Hz.
The performance of the 4-D 128SP-QAM format is experimentally investigated in a Nyquist-wavelength division multiplexing system for two different forward error correction (FEC) scenarios. Two ...soft-decisions FEC schemes are experimentally evaluated for 128SP-QAM, namely, a turbo product code (TPC) and a low-density parity-check (LDPC) code. The results show that after full convergence the LDPC code outperforms the TPC with respect to coding gain at a bit error ratio of 10 -8 . However, it requires more decoding iterations to achieve convergence toward an optimum performance state.
We present a novel framework that enables vendors and operators, with partial access to operational and monitoring features of a service, to collaboratively develop a ML-assisted solution without ...revealing any business-critical raw data to each other. We validate our proposal for a QoT estimation use-case.
We experimentally investigate polarization-switched quadrature phase-shift keying (PS-QPSK) with a symbol rate of 37.3 GBd corresponding to a bit rate of 112 Gb/s. In a wavelength-division ...multiplexing (WDM) experiment with 50 GHz channel spacing, the transmission performance of PS-QPSK is compared to that of polarization-division multiplexed QPSK (PDM-QPSK) over an EDFA amplified ultra-large-effective-area fiber link. For a bit-error ratio (BER) of 3.8 × 10(-3), the achieved transmission distance is 11000 km for PS-QSPK and 10000 km for PDM-QPSK.
In this contribution, we report on the experimental investigation of an ultra-dense wavelength-division multiplexing (UDWDM) upstream link with up to 700 × 2.488 Gb/s polarization-division ...multiplexing differential quadrature phase-shift keying parallel upstream user channels transmitted over 80 km of standard single-mode fiber. We discuss challenges of the digital signal processing in the optical line terminal arising from the joint reception of several upstream user channels. We present solutions for resource and cost-efficient realization of the required channel separation, matched filtering, down-conversion and decimation as well as realization of the clock recovery and polarization demultiplexing for each individual channel.
Religious rituals are ubiquitous. Recent research indicates they can powerfully affect social connection, increasing collective sentiments and behaviors. However, the extent to which these effects ...depend on religious commitment remains unclear. Here, we use longitudinal data to investigate this question in a natural ritual setting by comparing the responses of religiously committed Hindus and non-Hindus immediately after a public Diwali celebration in New Zealand, and for two weeks following. Effects of time and level of religious commitment are assessed on five targets that measure reported social connection of participants to themselves and to specific groups: "Myself," "My family and friends," "Work colleagues/university peers," "People who celebrate Diwali," and "Humanity in general." We find that participation in the civic religious ritual affects social connection of all participants, with stronger effects among religiously committed Hindus. Private religious behavior appears integral to the mechanisms underpinning the amplification of solidarity at public rituals, as we find separation in the level of reported social connection to Diwali celebrants between practicing and non-practicing Hindus. Though religious commitment leads to greater perceived social connection, this study additionally demonstrates that in a religiously diverse democracy, a civic religious ritual may foster greater democratic unions across religious differences.
A hybrid optical transmitter module comprising a 15-segment InP in-phase/quadrature-phase segmented Mach-Zehnder modulator and two SiGe:C BiCMOS drivers featuring integrated 4-b digital-to-analog ...converter functionality is described. The drivers, fabricated in the 0.13-μm process of IHP, deliver a differential output voltage of 2.5 V pp across all the 15 segments while dissipating less than 1 W of power each, at the maximum. Clear electrical eye diagrams up to 40-Gb/s from every output are reported. The module allows a wide range of modulation formats, among which up to eight-pulse amplitude modulation and polarization-division-multiplexed (PDM) 64-quadrature amplitude modulation (QAM) back-to-back error-free electro-optical transmission at a record speed of 32 GBd are demonstrated. The 32-GBd PDM 64-QAM signal was transmitted error-free over 80 km of standard single-mode fiber, featuring 7.8-pJ/b energy consumption. The devised hybrid arrangement proves the suitability of SiGe HBT drivers for achieving higher speeds over their CMOS counterparts, with comparable low power dissipation, for advanced optical transceivers.
We demonstrate the development of a QoT classifier over an autonomous machine-learning pipeline, the trading of the classifier over a federated marketplace, and eventually its deployment in the ...customer's network as a cloud-native micro-service.
We present a segmented Mach-Zehnder modulator, which allows for frequency equalization and narrow spectral shaping without the need of any high-resolution digital-to-analog converter and digital ...signal processing on the transmitter side. The spectral shaping is achieved with the use of resonant structures implemented in the InP chip. This novel component is employed to transmit 320 Gb/s over 80 km of standard single mode fiber on two subcarriers modulated with dual-polarization pulse-amplitude modulation-4. Thanks to the modulator spectral shaping, the spacing between the two subcarriers is as little as 50 GHz. With an overall occupied bandwidth of 100 GHz, the gross spectral efficiency is 3.2 bit/s/Hz.
A hybrid transmitter module comprising a 15-segment InP IQ segmented Mach-Zehnder modulator and two 0.13 μm BiCMOS SiGe:C drivers with integrated 4-bit DAC functionality is described. The ...high-resolution prototype allows a wide range of modulation formats and, for the first time, ultralow-power dual-polarization (DP) 64-QAM signal generation at record speed of 32 GBd without the usage of external DACs is demonstrated. The DP 64-QAM signal is transmitted error free over 80 km of SSMF with 7.8 pJ/bit/polarization energy consumption. Post-FEC BER results are presented, with more than 2 26 bits decoded without errors after four decoding iterations. The package footprint is 28 mm × 76 mm. These results evidence the advantage of the proposed arrangement for the next generation low-power high-speed optical transceivers.
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