Ken Mishina

We propose an all-optical modulation format conversion scheme from non-return-to-zero on-off-keying (NRZ-OOK) to return-to-zero (RZ) multiple-level phase-shift-keying (PSK) based on nonlinearity in optical fiber. The proposed conversion scheme is numerically investigated and experimentally demonstrated. We experimentally demonstrate error-free operation of NRZ-OOK/RZ- binary PSK conversion at 10.7 Gb/s. The operation of the NRZ-OOK/RZ-quadrature PSK conversion is shown by eye opening after balan

A novel all-optical modulation format conversion from non-return-to-zero on-off-keying (NRZ-OOK) to return-to-zero quadrature-phase-shift-keying (RZ-QPSK) is proposed and experimentally demonstrated. The proposed format conversion scheme is based on parallel Mach-Zehnder interferometric (MZI) OOK/binary-PSK (BPSK) converters, consisting of integrated semiconductor optical amplifiers (SOAs). We experimentally demonstrate that in both decoded channels of the converted RZ-QPSK signal bit error rate

Optical eigenvalue communication is a promising technique for overcoming the Kerr nonlinear limit in optical communication systems. The optical eigenvalue associated with the nonlinear Schrödinger equation remains invariant during fiber-based nonlinear dispersive transmission. However, practical applications involving use of such systems are limited by the occurrence of fiber loss and amplified noise that induce eigenvalue distortion. Thus, several time-domain neural-network-based approaches hav

A number of all-optical signal processing schemes based on nonlinear optical effects have been proposed and demonstrated for use in future photonic networks. Since various modulation formats have been developed for optical communication systems, all-optical converters between different modulation formats will be a key technology to connect networks transparently and efficiently. This paper reviews our recent works on all-optical modulation format conversion technologies in order to highlight the

Eigenvalue-based communication technologies using inverse scattering transform (IST) have gained attention as a new transmission strategy in optical fiber communications. In recent years, several studies on artificial neural network (ANN)-based equalization and demodulation schemes for eigenvalue-modulated signal have been conducted to enhance the receiver sensitivity. However, in the case of a presence of a carrier frequency offset (CFO) at receiver, the effects of the CFO on ANN receiver of ei

We propose a novel all-optical NRZ-OOK/RZ-BPSK format conversion scheme, using cross-phase modulation effects in a MZI-SOA. We experimentally demonstrate error free conversion at 10.7 Gb/s with a negative power penalty of 2.9 dB

We propose a novel all-optical NRZ-OOK/RZ-16QAM modulation format converter using parallelized SOA-MZIs and show the feasibility of the proposed scheme by numerical simulation at 10 GSymbol/s.

A demodulation scheme for an eigenvalue modulated signal based on an eigenvalue-domain neural network is demonstrated experimentally. Successful demodulation is demonstrated at 2.5 Gb/s over a transmission distance of up to 3,000 km.

Optical eigenvalue transmission based on inverse scattering transform (IST) has been studied for one of approaches to overcome the Kerr nonlinearity limit in fiber optic communications. In the recent decade, several multilevel modulation schemes that are based on IST, such as 16-ary and 64-ary signals using on-off encoding and b-modulation of multieigenvalues, have been proposed. To increase the transmission capacity and extend the transmission distance, applications of machine learning-based ap

We propose a novel sensing method to detect an abnormal noise point using the nonlinear Fourier transform. High estimation accuracy of the proposed method within 0.1 km is demonstrated by numerical simulation.

We propose the application of an SD-FEC technique to an eigenvalue-modulated signal using a multilabel neural-network demodulator. The experimental results indicate a successful operation with an error-free transmission through a 3000-km optical fiber line.

The generalization performance of an artificial neural network-based demodulator for an eigenvalue modulated signal is investigated. Successful demodulation for transmission distances from zero to 3,000 km and carrier frequency offset within 1 GHz is demonstrated.

We have proposed a novel all-optical NRZ-OOK/RZ-QPSK modulation format converter using parallel SOA-MZIs in a MZI configuration. We experimentally demonstrate an error-free operation of the proposed modulation format conversion at 10.7 Gsymbol/s.