Tomoo Takahara

Experimental demonstration of 448-Gbps+ DMT transmission over 30-km SMF

We have experimentally demonstrated 469-Gbps transmission over 30-km SMF using DMT on a LAN-WDM system for 400-Gbps Ethernet. Only four directly modulated lasers and direct detectors as optical devices were necessary to achieve the results.

100 Gb/s optical IM-DD transmission with 10G-class devices enabled by 65 GSamples/s CMOS DAC core

100 Gb/s optical IM-DD transmission over 10 km SMF is experimentally demonstrated by using discrete multi-tone and CMOS DAC core. The limiting factors towards further reach extension are investigated.

40-Gb/s WDM transmission with virtually imaged phased array (VIPA) variable dispersion compensators

We have demonstrated variable dispersion compensation by using a virtually imaged phased array (VIPA) to overcome the small dispersion tolerance in 40-Gb/s dense wavelength-division multiplexing (WDM) transmission systems. By utilizing the periodical characteristics of VIPA compensators, we performed simultaneous dispersion compensation in a 1.28-Tb/s (40-Gb/s/spl times/32 ch; C band) short-haul transmission and confirmed that only two VIPA compensators and one fixed dispersion-compensating fiber are required for a large transmission range of 80 km. This performance can greatly reduce the cost, size, and number of compensator menus in a 40-Gb/s WDM short-haul transmission system. In addition, we achieved 3.5-Tb/s (43-Gb/s/spl times/88 ch; C and L bands) transmission over a 600-km nonzero dispersion-shifted fiber by using VIPA compensators. Although channel-by-channel dispersion compensation is required due to the larger residual dispersion slope in long-haul transmission, the periodical characteristics of the VIPA compensators offer the advantage of considerably reducing the number of different modules required to cover the whole C (or L) band. An adequate optical signal-to-noise ratio, which was the same for all channels, was-obtained by using distributed Raman amplification, a gain equalizer, and a preemphasis technique. We achieved a Q-factor of more than 11.8 dB; (BER<10/sup -17/ with forward-error correction) for all 88 channels.

80 km IM-DD transmission for 100 Gb/s per lane enabled by DMT and nonlinearity management

117Gb/s single wavelength and polarization IM-DD transmission over 40km SMF is first enabled by DMT. With an SOA, 101Gb/s over 80km is demonstrated. The nonlinearity management through parameter optimization and digital compensation is discussed.

SDN-Based Network Orchestration of Variable-Capacity Optical Packet Switching Network Over Programmable Flexi-Grid Elastic Optical Path Network

A multidomain and multitechnology optical network orchestration is demonstrated in an international testbed located in Japan, the U.K., and Spain. The application-based network operations architecture is proposed as a carrier software-defined network solution for provisioning end-to-end optical transport services through a multidomain multitechnology network scenario, consisting of a 46-108 Gb/s variable-capacity OpenFlow-capable optical packet switching network and a programmable, flexi-grid elastic optical path network.

Discrete Multi-Tone for 100 Gb/s optical access networks

Discrete Multi-Tone (DMT) is an attractive technology for short reach optical transmission systems. We have reported several results on transmission experiments using DMT. In this paper we review this technology and these experimental results.

SDN-Enabled Sliceable BVT Based on Multicarrier Technology for Multiflow Rate/Distance and Grid Adaptation

We propose a sliceable bandwidth variable transceiver (S-BVT) architecture suitable for metro/regional elastic networks and highly scalable data center applications. It adopts multicarrier modulation, either OFDM or DMT, and a cost-effective optoelectronic front-end. The high-capacity S-BVT is programmable, adaptive, and reconfigurable by an SDN controller for efficient resource usage, enabling unique granularity, flexibility, and grid adaptation, even in the conventional fixed-grid networks. We experimentally demonstrate its multiple advanced functionalities in a four-node photonic mesh network. This includes SDN-enabled rate/distance adaptive multiflow generation and routing/switching, slice-ability, flexibility, and adaptability for the mitigation of spectrum fragmentation, as well as for a soft migration toward the flexi-grid paradigm.

Experimental investigation of 100-Gbps transmission over 80-km single mode fiber using discrete multi-tone modulation

We experimentally evaluated the transmission performance of discrete multi-tone (DMT) modulation at wavelengths in the 1300-nm and 1550-nm regions and analyzed the degradation factors. By using their countermeasures to extend transmission distance, we realized the capacity of 100 Gbps with 2WDM x 50 Gbps over 80 km. To our knowledge, this work is the highest capacity in 80-km transmission system using direct modulation and direct detection. These results show that the DMT modulation can be used to realize high capacity transceiver with simple and cost effective configuration for the bi-directional transmission system like a passive optical network.

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.

Digital signal processing for short reach optical links

Digital signal processing enabled coherent 100/400Gbit/s transceivers for long-reach links. Short-reach (<;100km) links also demand 100/400Gbit/s but more stringent cost, size, and power consumption requirements need to be addressed. Potential modulation formats and signal processing methods are discussed.