Ryo Okabe

An Optical Parametric Amplified Fiber Switch for Optical Signal Processing and Regeneration

An optical parametric amplified (OPA) fiber switch is described in this paper. This device switches input signals without shifting the wavelength by changing the polarization state of the signal using optical parametric amplification. The OPA fiber switch features ultra-broadband, highly efficient switching with a high contrast ratio. We experimentally test the prototype of the OPA fiber switch, which uses a highly nonlinear fiber. Optical demultiplexing of 160 Gb/s differential phase-shift keying (DPSK) signals is demonstrated in the whole C-band and shows that it provides almost penalty-free optical detection. The application of amplitude noise suppression with the OPA fiber switch by using parametric gain saturation is then proposed and demonstrated for a 160 Gb/s DPSK signal. When it is set to an amplitude-limiting condition, the OPA fiber switch successfully increases the optical signal-to-noise ratio by 4 dB and effectively suppresses the phase deterioration in 160 Gb/s DPSK transmission by increasing the system margin by more than 5 dB.

All-Optical Data Frequency Multiplexing on Single-Wavelength Carrier Light by Sequentially Provided Cross-Phase Modulation in Fiber

A novel configuration for an all-optical bus-topology data-multiplexing system is proposed in which multichannel signals are sequentially multiplexed by frequency-division multiplexing (FDM) on a single-wavelength optical carrier by cross-phase modulation (XPM) in nonlinear fibers (NLFs) with subcarrier-modulated optical data signals. By using highly NLFs for XPM generators and providing amplitude-modulated subcarrier-multiplexed optical signals generated with directly modulated lasers or optical beat signals at multiple local connection points, we successfully demonstrate sequential all-optical FDM of data signals on a single-wavelength optical carrier followed by error-free data transmission through a standard fiber.

Demonstration of Adaptive SDN Orchestration: A Real-Time Congestion-Aware Services Provisioning Over OFDM-Based 400G OPS and Flexi-WDM OCS

In this Paper, we experimentally demonstrate highly flexible and intelligent interdomain coordinated actions based on adaptive software-defined networking (SDN) orchestration. An advanced multidomain multitechnology testbed is implemented, which consists of a 400-Gb/s variable capacity optical packet switching domain and a Tb/s-class flexi-grid wavelength division multiplexed optical circuit switching domain. The SDN-controllable transponders and the extended transport applications programming interface enable the congestion-aware provisioning of end-to-end real-time services. At the data plane level, different transponders based on orthogonal frequency division multiplexing are employed for inter/intradomain links in order to adaptively provision services with fine granularity. For adaptation, SDN-capable domain-specific optical performance monitors are also introduced. In the control plane, the applications based network operations architecture has been extended and addressed as an adaptive SDN orchestrator.

Multi-stage optical FDM of 12-channel 10-Gb/s data with 20-GHz exact channel spacing using fiber cross-phase modulation with optical subcarrier signals

A sequential optical frequency-division multiplexing technique using cross-phase modulation in fibers with exactly frequency-controlled optical subcarrier signals is proposed and demonstrated. 12 channels of 10-Gb/s ASK/DPSK signals with 20-GHz exact channel spacing are successfully multiplexed all-optically at 12 stages with 1-km intervals.

Polarization-independent all-optical amplitude limiter using two-stage gain-saturated fiber parametric amplifiers

A polarization-independent optical limiter is proposed using two-stage polarization-diversity configured optical parametric amplifiers in gain-saturated condition. Its amplitude level equalizing effect is successfully demonstrated for a 40 Gb/s signal with less than 0.2 dB polarization dependence.

Novel demultiplexer for ultra high speed pulses using a perfect phase-matched parametric amplifier

A novel transparent demultiplexer for ultra fast pulse trains using a 19 m long HNLF-based parametric amplifier is proposed. Using this multiplexer, 320-10 Gb/s OTDM DEMUX with parametric gains over 20 dB were successfully implemented

100G beyond Ethernet transport for inter- and intra-DCN communication with solutions and optical enabling technologies in the ICT STRAUSS project

A multi-domain optical infrastructure with end-to-end Ethernet transport capability can deliver Ethernet services over a large scale and provide a promising solution for inter data center networks (DCN) communication. The already existed metro and core networks should be evolved both in data plane and control plane towards to support the heterogeneous and dynamic Ethernet traffic environment. In this paper, we report the work carried out in the ICT STRAUSS project to provide Ethernet connections for intra-DCN and inter-DCN over metro and core networks. The key technologies for intra- and inter- DCN communications are reported with experimental validation.

100 Gb/s optical discrete multi-tone transceivers for intra- and inter-datacenter networks

Discrete multi-tone (DMT) technology is an attractive modulation technology for short-reach application due to its high spectral efficiency and simple configuration. In this paper, we first explain the features of DMT technology then discuss the impact of fiber dispersion and chirp on the frequency responses of the DMT signal and the importance in the relationship between chirp and the optical transmission band. Next, we explain our experiments of 100-Gb/s DMT transmission of 10 km in the O-band using directly modulated lasers for low-cost application. In an inter-datacenter network of more than several tens of kilometers, fiber dispersion mainly limits system performance. We also discuss our experiment of 100-Gb/s DMT transmission up to 100 km in the C-band without a dispersion compensator by using vestigial sideband spectrum shaping and nonlinear compensation.

Investigation of fiber dispersion impairment in 400GbE discrete multi-tone system for reach enhancement up to 40 km

Discrete multi-tone (DMT) technology is an attractive modulation technique for short reach optical transmission system. One of the main factors that limit system performance is fiber dispersion, which is strongly influenced by the chirp characteristics of transmitters. We investigated the fiber dispersion impairment in a 400GbE (4 × 116.1-Gb/s) DMT system on LAN-WDM grid for reach enhancement up to 40 km through experiments and numerical simulations.

Digital signal processing for short haul optical data communication systems

Digital Signal processing is going on spreading from long reach systems to short reach systems. Especially Discrete Multi-Tone is an attractive technology for short reach optical transmission systems. In this paper we review this technology.