Coriant (Germany)

Flapping flight is inherently unstable, requiring Drosophila to fine-tune their wing motions on a milliseconds timescale. Pioneering studies have shown that the direct steering muscles, which attach to the wing hinge, are important for generating these rapid flight reflexes. Recent connectome data, however, reveal that indirect steering muscles or tension muscles, which alter the mechanics of the thorax, receive some of the same synaptic inputs from the sensory apparatus as the direct steering muscles. This discovery suggests that the indirect steering muscles may also be important for flight control. Here, we show that the indirect tergopleural muscles indeed contribute substantially to stabilization, particularly for large pitch perturbations. We find that for small perturbations (less than 1000 deg/s), flies modulate their wing stroke amplitude to generate lift-based corrective torques, a strategy that has been previously documented. For larger perturbations, however, we observe that Drosophila engage an additional wing degree of freedom—the wing pitch angle—to leverage additional lift and drag forces during the corrective maneuver. Quasi-steady aerodynamic simulations reveal that this strategy minimizes power consumption, anaolgous to how some mammals (including humans) adjust their steady-state gaits in a near energy-optimal manner. Using optogenetics and a control theory framework we demonstrate that the tergopleural muscle is activated by a proportional gain component of a nonlinear PI controller responsible for determining the wing pitch angle during large perturbations. A simplified torsional-spring model for the wing hinge captures the changes in the wing pitch dynamics observed during correction maneuvers by using the tergopleural muscle to adjust the rest angle of the wing. These findings provide a striking example of reflex strategy selection in time-critical behaviors and underscores the vital role of indirect steering muscles in flight stabilization.

<p>D3.2 reports the first validation of the METRO-HAUL node architecture and the interconnection, transmission and switching optical solutions developed in T3.1-T3.3 in different disaggregated scenarios. The deliverable also includes an early description of the METRO-HAUL node control and management environment and the developed software for controlling all the OIE developed in T3.4.</p>

In this paper, we discuss the state-of-the-art of components and technology to enable multi-band transmission over single mode fibers (SMFs). A full overview on the most relevant challenges is provided.

In this paper, a simulation model of a multicore fiber in the linear regime is presented. We describe how to digitally represent the fiber and introduce a modelling scheme based on Coupled-Mode theory and Power-Coupled theory to analyze the system performance of multicore fibers. In order to validate the investigated model, the obtained simulation results are compared to our own measurements of a 7-core multicore fiber transmission link and to results from previously published experiments.

We present a robust adaptive digital pre-distortion technique to mitigate the linear and non-linear degradation of optical communication transmitter components. The proposed method is based on the principles of memory polynomial based pre-distortion and indirect learning architecture. Effectiveness of the presented algorithm is assessed across various higher order modulation formats and higher baud rates. Significant gains are reported in back-to-back measurements and various lab and field trial experiments.

We report on the results of a field trial carried out on a Telecom Italia metro link, targeting short data center interconnect applications. The test-bed presented realistic transmission conditions, such as an average ~0.3-dB/km attenuation and usage of legacy erbium-doped fiber amplifier (EDFA) only. We transmitted a net bit rate of 400 Gb/s on a single carrier with 64 quadrature amplitude modulation (QAM) and 128QAM over 156 km. Error-free transmission over 80 km for single carrier dense wavelength-division multiplexing (DWDM) $30\times 400\text{G}$ 64QAM and $30\times 400\text{G}$ 128QAM (one half of the $C$ -band) is reported. The net spectral efficiency, for both schemes, is 7.11 b/s/Hz.

In this paper, we present long-haul 32-core dense space-division-multiplexed (DSDM) unidirectional transmission over a single-mode multicore transmission line. We developed a low-crosstalk heterogeneous 32-core fiber with a square lattice arrangement, and a novel partial recirculating loop system. The span crosstalk of the 51.4-km 32-core transmission line was less than –34.5 dB. This allowed the transmission of polarization-division-multiplexed 16 quadrature amplitude modulation (PDM-16QAM) signals through all 32 cores over a long distance exceeding 1000 km. We demonstrate 32-core DSDM 20 wavelength-division-multiplexed PDM-16QAM transmission over 1644.8 km with a high aggregate spectral efficiency of 201.46 b/s/Hz Additionally, we examine the effect of crosstalk on the transmission performance of each core, and show that the Q-penalty has strong correlation with intercore crosstalk.

We demonstrate next-generation network upgrade scenarios using flexi-format (PM-QPSK→PM-64QAM) and flexi-rate (100G→300G) transmission over field-deployed fiber (762km). The back-to-back penalties are limited to ∼2.6dB, whereas after transmission, available margin in excess of ∼7.6dB is reported.

We present a linear and nonlinear digital predistortion (DPD) tailored to the components of an optical transmitter. The DPD concept uses nonlinear models of the transmitter devices, which are obtained from direct component measurements. While the digital-to-analog converter and driver amplifier are modeled jointly by a Volterra series, the modulator is modeled independently as a Wiener system. This allows for block-wise compensation of the modulator by a Hammerstein system and a pre-distortion of the electrical components by a second Volterra series. In simulations and extensive experiments, the performance of our approach for nonlinear DPD is compared to an equivalent linear solution as well as to a configuration without any digital pre-distortion. The experiments were performed using M-ary quadrature-amplitude modulation (MQAM) formats ranging from 16-QAM to 128-QAM at a symbol rate of 32 GBd. It is shown that DPD improves the required optical signal-to-noise ratio at a bit error ratio of 2???10-2 by at least 1.2 dB. Nonlinear DPD outperforms linear DPD by an additional 0.9 dB and 2.7 dB for higher-order modulation formats such as 64-QAM and 128-QAM, respectively.

This paper aims to review the status of standardization activities on the black link (BL) and corresponding alien wavelength concepts. It discusses experimental work on filterless optical networks conducted within a dedicated Deutsche Telekom project. The general prospects and existing challenges concerning elastic extensions of the BL are also assessed. Furthermore, we present relevant work on control and management plane interoperability comprising generalized multi-protocol label switching and transport software defined networking aspects. In the second part of the article, we report on the latest dual-vendor experiments on data plane interoperability in terms of digital signal processing technology for next generation 1.28 Tb/s PM-16QAM super-channels. Finally, we present a network reachability analysis based on the widely used Gaussian noise model in the context of data plane interoperability. This analysis estimates the network-wide impact of the single-vendor versus the dual-vendor approach.