Takehito Tanaka

40 Gb/s Low-drive-voltage LiNbO 3 Optical Modulator for DQPSK Modulation Format

Low-drive-voltage (3.5 V) and uniform modulation characteristics of MZIs were achieved with Z-cut dual-drive nested-MZIs structure and the wide-gap design between signal and ground electrodes, resulting in precise constellation mappings in 43 Gb/s DQPSK modulation.

1.05 Tbit/s WDM transmission over 8,186 km using distributed Raman amplifier repeaters

We have achieved a 1.05 Tera bit/s WDM transmission over 8186 km using distributed Raman amplifier repeaters. Signal bandwidth was 31.2 nm and the optical SNR improvement was about 1.5 dB in contrast to using an EDFA repeater.

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.

Unrepeated 100 km SMF transmission of 110.3 Gbps/lambda DMT signal

We experimentally demonstrate 110.3 Gbps/lambda DMT transmission over 100 km SMF without chromatic dispersion compensation. Transmission reach extension is achieved by suppression of power fading of chromatic dispersion and nonlinearities using combination of VSB and NLC.

PDL-induced noise reduction in long-haul transmission systems using synchronous polarization scrambling

We proposed polarisation dependent loss (PDL) induced noise reduction method using a band-rejection-filter in a long-haul large-capacity WDM transmission system with synchronous polarization scrambling. We demonstrated the effect in an 8 channel 5.332 Gbit/s WDM transmission experiment using this method.

Control orchestration protocol: Unified transport API for distributed cloud and network orchestration

In the context of the fifth generation of mobile technology (5G), multiple technologies will converge into a unified end-to-end system. For this purpose, software defined networking (SDN) is proposed, as the control paradigm will integrate all network segments and heterogeneous optical and wireless network technologies together with massive storage and computing infrastructures. The control orchestration protocol is presented as a unified transport application programming interface solution for joint cloud/network orchestration, allowing interworking of heterogeneous control planes to provide provisioning and recovery of quality of service (QoS)-aware end-to-end services. End-to-end QoS is guaranteed by provisioning and restoration schemes, which are proposed for optical circuit/packet switching restoration by means of signal monitoring and adaptive modulation and adaptive route control, respectively. The proposed solution is experimentally demonstrated in an international multi-partner test bed, which consists of a multi-domain transport network comprising optical circuit switching and optical packet switching domains controlled by SDN/OpenFlow and Generalized Multiprotocol Label Switching (GMPLS) control planes and a distributed cloud infrastructure. The results show the dynamic provisioning of IT and network resources and recovery capabilities of the architecture.

Demonstration of dynamic congestion control in optical packet switching network employing rate-adaptive transmitter and receiver

We experimentally demonstrate dynamic congestion control in an optical packet switching network employing an optical packet counter for traffic flow diagnosis and a rate-adaptive transmitter and receiver to reduce packet loss ratio while preserving the transmission capacity.

Comparison between dispersion management for long-haul WDM systems using all-Raman-amplifier repeaters

We have numerically and experimentally compared the performance, in a WDM transmission system in which all repeaters are Raman amplifiers, of our proposed chromatic dispersion management and of a conventional dispersion management. The performance of our management was 1.6-dB better than that of the conventional management. Applying our management improved the OSNR by about 0.6 dB and reduced the amount of waveform distortion due to the nonlinear effect and group-velocity dispersion by 1.0 dB. We are convinced that our proposed dispersion management will be very effective for use with long-haul, high-capacity transmission systems in which all repeaters are Raman amplifiers and can be the best solution for the distributed Raman fibre amplification based system.