Takaya Miyazawa

Software defined networking (SDN) over space division multiplexing (SDM) optical networks: features, benefits and experimental demonstration

We present results from the first demonstration of a fully integrated SDN-controlled bandwidth-flexible and programmable SDM optical network utilizing sliceable self-homodyne spatial superchannels to support dynamic bandwidth and QoT provisioning, infrastructure slicing and isolation. Results show that SDN is a suitable control plane solution for the high-capacity flexible SDM network. It is able to provision end-to-end bandwidth and QoT requests according to user requirements, considering the unique characteristics of the underlying SDM infrastructure.

Fully-elastic multi-granular network with space/frequency/time switching using multi-core fibres and programmable optical nodes

We present the first elastic, space division multiplexing, and multi-granular network based on two 7-core MCF links and four programmable optical nodes able to switch traffic utilising the space, frequency and time dimensions with over 6000-fold bandwidth granularity. Results show good end-to-end performance on all channels with power penalties between 0.75 dB and 3.7 dB.

Development of optical packet and circuit integrated ring network testbed

We developed novel integrated optical packet and circuit switch-node equipment. Compared with our previous equipment, a polarization-independent 4 × 4 semiconductor optical amplifier switch subsystem, gain-controlled optical amplifiers, and one 100 Gbps optical packet transponder and seven 10 Gbps optical path transponders with 10 Gigabit Ethernet (10GbE) client-interfaces were newly installed in the present system. The switch and amplifiers can provide more stable operation without equipment adjustments for the frequent polarization-rotations and dynamic packet-rate changes of optical packets. We constructed an optical packet and circuit integrated ring network testbed consisting of two switch nodes for accelerating network development, and we demonstrated 66 km fiber transmission and switching operation of multiplexed 14-wavelength 10 Gbps optical paths and 100 Gbps optical packets encapsulating 10GbE frames. Error-free (frame error rate < 1×10(-4)) operation was achieved with optical packets of various packet lengths and packet rates, and stable operation of the network testbed was confirmed. In addition, 4K uncompressed video streaming over OPS links was successfully demonstrated.

Development of an Autonomous Distributed Control System for Optical Packet and Circuit Integrated Networks

In this paper, we describe an autonomous distributed control system that we have been developing for an optical packet and circuit integrated network, and we experimentally evaluate its performance. Colored (i.e., multi-wavelength) optical packet-switched links transfer both control signals for circuit switching (e.g., signaling and routing) and best-effort packet data. We successfully transmitted high-definition uncompressed real-time video signals on two lightpaths established by our control system without degradation of video quality, simultaneously with other optical packet data transferred on the same optical fibers. Our developed control system not only achieved autonomous distributed signaling and routing but also has a function that can adjust wavelength resources for optical packet and circuit switching autonomously in each link at each node. Controllers achieved lightpath establishment within approximately 360 ms and dynamic resource adjustment within approximately 454 ms, in the best possible case in our experimental setup.

Enhancement of tolerance to MAIs by the synergistic effect between M-ary PAM and the chip-level receiver for optical CDMA systems

In this paper, an M-ary pulse-amplitude modulation (PAM) coded optical code division multiple access (CDMA) system applying the chip-level receiver with M-level threshold detection is proposed. First, in order to increase the number of transmitted bits per pulse, the PAM coded system is considered. However, when the correlator is applied in the receiver, the multiple access interferences (MAIs) with high intensities deteriorate the system performance significantly even if the number of MAIs is small. Consequently, the chip-level receiver with M-level threshold detection instead of the correlator in the M-ary PAM-CDMA system is proposed. The proposed system can obtain the synergistic effect between the PAM and the chip-level receiver, in which the chip-level receiver reduces more MAIs compared with the correlator and the PAM has the larger number of transmitted bits per frame than ON-OFF keying (OOK). As a result, the proposed system can increase the code length and the number of weights, and achieves higher tolerance to MAIs than the OOK-CDMA system with the chip-level receiver under the condition in which the chip duration, the bit rate, and the number of subscribers are kept constant. It is shown that the proposed M-ary PAM-CDMA system with the chip-level receiver achieves better bit error probability (BEP) than the OOK-CDMA system with the chip-level receiver.

Control-message exchange of lightpath setup over colored optical packet switching in an optical packet and circuit integrated network

We have proposed the concept of an optical packet and circuit integrated network to provide service diversity, energy efficiency and a simplified control mechanism toward new generation networks. In this integrated network, optical data packets and data on lightpaths are transmitted on common physical resources for efficient resource use. In addition, path signaling for lightpath setup and release thorough optical packet switch block is implemented. We set up a primitive optical packet and circuit integrated network including one switching node and a set of packet/path transceiver. We demonstrate 80 (8λ × 10) Gbit/s colored optical packet switching and 8-lightpaths establishment by transferring optical control packets over the optical packet switching.

First development of integrated optical packet and circuit switching node for new-generation networks

We develop an integrated optical packet and circuit switching node in which signaling via optical packet switching is implemented. We demonstrate 80 (8λ × 10) Gbit/s optical packet switching with <1E-4 packet-loss-rate, 8-lightpaths establishment, and dynamic wavelength-resources control.

BER Performance Analysis of Spectral Phase-Encoded Optical Atmospheric PPM-CDMA Communication Systems

We propose spectral phase-encoded optical atmospheric (OA) code-division multiple-access (CDMA) systems with pulse-position modulation (PPM) and theoretically analyze the bit error rates (BERs). We compare the BERs of the proposed system to those of time-encoded OA-PPM-CDMA systems at the same bit rate and chip rate. We show that, even if the proposed spectral phase-encoded OA-PPM-CDMA system is equipped with no mitigation techniques of multiple access interference (MAI) and scintillation, the proposed system achieves lower BERs than both time-encoded OA-PPM-CDMA systems, both with and without a mitigation technique of MAI/scintillation, due to its higher code spreading gain and higher tolerance to noise.

Multirate and multiquality transmission scheme using adaptive overlapping pulse-position modulator and power controller in optical CDMA networks

We propose the multirate and multiquality transmission scheme using adaptive overlapping pulse-position modulator (OPPM) and optical power controller in optical CDMA networks. In the proposed system, the multirate and the multiquality transmission can be achieved by accommodating users with the different value of M and the different transmitted power in the same network. The proposed scheme has the advantage that it is not required to change the code-length and weight depending on the required bit-rate of the user and the difference of the bit-rates does not have so much effect on the bit error probabilities (BEPs). Moreover, the difference of the power does not cause the change of bit-rate. We analyze the BEPs of the four multimedia service classes corresponding to the combinations of high/low-rates and high/low-qualities, and show that the proposed scheme can easily achieve distinct differentiation of the service classes with the simple system configuration.

Moving the boundary between wavelength resources in optical packet and circuit integrated ring network

Optical packet and circuit integrated (OPCI) networks provide both optical packet switching (OPS) and optical circuit switching (OCS) links on the same physical infrastructure using a wavelength multiplexing technique in order to deal with best-effort services and quality-guaranteed services. To immediately respond to changes in user demand for OPS and OCS links, OPCI networks should dynamically adjust the amount of wavelength resources for each link. We propose a resource-adjustable hybrid optical packet/circuit switch and transponder. We also verify that distributed control of resource adjustments can be applied to the OPCI ring network testbed we developed. In cooperation with the resource adjustment mechanism and the hybrid switch and transponder, we demonstrate that automatically allocating a shared resource and moving the wavelength resource boundary between OPS and OCS links can be successfully executed, depending on the number of optical paths in use.