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We demonstrate the first 1-Pb/s unidirectional inline-amplified transmission over 205.6-km of single-mode 32-core fiber within C-band only. 96-Gbaud LDPC-coded PDM-16QAM channels with FEC redundancy of 12.75% realize high-aggregate spectral efficiency of 217.6 b/s/Hz.
In designing a vacuum equipment such as Vacuum Interrupters (VIs), it is one of the important factors to grasp the characteristics of surface flashover in vacuum, which occurs via charging of the insulator. In this study, we measured the charge distribution characteristics inside a bottle type insulator as the model insulator of VI after the AC voltage application. This insulator has shield rings...
An ultra-broadband 2∶1 analog-multiplexer (A-MUX) module has been developed for optical communications systems with a high symbol rate. The A-MUX IC was designed and fabricated using in-house InP HBTs, which have a peak ft and fmax of 290 and 320 GHz, respectively. The A-MUX module has a through bandwidth of over 50 GHz and operates at a clock rate of up to 50 GHz, leading to 100-GS/s operation. Its...
This paper presents a design method of model reference robust adaptive control systems (MRRACS) with fixed compensator for a single-input single-output (SISO) linear time-invariant continuous-time plant in the presence of bounded unknown deterministic disturbances and unmodeled dynamics. The fixed compensator is designed based on H∞-optimal theory. The aim of the proposed control structure...
An adaptive MIMO equalization method is presented for few-mode fiber transmission where various differential mode delays (DMDs) simultaneously occur. Evaluation using experimental data shows its use of sparsity to promote equalization effectively deals with various DMDs to suppress the noise.
This paper presents a slip control strategy for a wheeled mobile robot which consists of two modules: a normal wheeled vehicle, and a moveable auxiliary mass which is a feature of this mobile robot. Longitudinal motion of the auxiliary mass can be controlled by a DC motor to improve the vehicle mobility. That is, the auxiliary mass is utilized to change the center of gravity and the moment of inertia...
We demonstrate 12-core × 3-mode dense SDM transmission over 527 km graded-index multi-core few-mode fiber without mode-dispersion management. Employing low baud rate multi-carrier signal and frequency-domain equalization enables 33.2-ns DMD compensation with low computational complexity.
This paper presents a new on-line adaptive identification of physical model parameters by adjusting the parameters in the feedforward controller and feedback PI controller for a motor drive system. The proposed scheme is characterized by new set-up of a suitable reference model which generates signals needed to identify the physical parameters of a two-mass motor system, such as inertia moments of...
The corrected least squares (CLS) approach using an over-determined model is investigated to decide the number of sinusoids in additive white noise. Like the total least squares (TLS) approach, the CLS estimation is different from the ordinary least squares (LS) method in that the noise variance is subtracted from the diagonal elements of the correlation matrix of the noisy observed data. Therefore...
We demonstrate dense SDM transmission of 20-WDM multi-carrier PDM-32QAM signals over a 40-km 12-core × 3-mode fiber with 247.9-b/s/Hz spectral efficiency. Parallel MIMO equalization enables 21-ns DMD compensation with 61 TDE taps per subcarrier.
We demonstrate 12-core fiber bidirectional long-haul transmission with sub-petabit-class capacity (2 × 344 Tb/s). Inter-core crosstalk management and multicarrier nonlinear compensation enabled the longest distance of 1500 km in SDM transmission with unidirectional capacity over 300 Tb/s.
High-order QAM offers the high spectral efficiency and high capacity. PDM-64QAM with single-carrier frequency-division-multiplexing (SC-FDM) enhanced by pilot-tone-based phase noise compensation is proposed and shown to achieve high-capacity transport with 400Gb/s-class high speed channels.
We investigate long-haul WDM transmission using 538Gb/s PDM-64QAM single-carrier frequency-division-multiplexing (SC-FDM) signal with pilot tone. Assuming 20% FEC overhead, the longest transmission distance of 1200km at the spectral efficiency of 8.96b/s/Hz is achieved.
We demonstrate 102.3 Tb/s transmission over 3×80 km of PSCF by employing 548-Gb/s PDM-64QAM single-carrier frequency-division-multiplexing (SC-FDM) signals with pilot tone and 11.2-THz ultra-wideband low-noise amplification in the C- and extended L-bands.
Frequency-domain equalization (FDE) has been attracting much attention for high-speed long-haul transmission over fiber-optic channels. Two FDE configurations for coherent optical transmission are presented and some applications are also described.
Nonlinear compensation with digital back-propagation can improve Q-factor by more than 1dB, proven by experiments. Simplification of propagation model is the key to suppress circuit size, whereas straight-forward implementation reaches 30-times larger than linear equalizers.
We succeed in the long-haul (1,280km) transmission of a 120-Gb/s PDM 64-QAM signal. The transmission distance was extended from 800 km to 1,280 km by a multi-stage nonlinear compensation technique that mitigates the intra-channel nonlinearities.
We demonstrate 45.2Tb/s 50-GHz-spaced WDM transmission over 240km (3 × 80km) in C-band using 538 Gb/s PDM-64QAM single-carrier frequency-division-multiplexed (SC-FDM) signal with digital pilot tone. Nonlinear tolerance is enhanced at spectral efficiency of 10b/s/Hz.
This paper addresses the problem of estimating the two-dimensional direction-of-arrival (2D DOA) of multiple narrowband signals impinging on an L-shaped array, which is structured by two uniform linear arrays (ULAs). A computationally efficient method without eigendecomposition is proposed, where the elevation angles are estimated from the cross-correlation matrices between the received data of two...
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