（2）英文要約
Title:
Project for Innovative AI Chips and Next-Generation Computing Technology Development
Development of Next Generation Computing Technologies
Research and Development of High Speed and Low Power Data Transfer System Using Photonic &Electronic Hybrid Switch for Next Generation Datacenter with Disaggregation Architecture(FY2018-FY2022)< Photoelectric hybrid switch (SW) control technology >To achieve high-speed switching in the photoelectric hybrid SW system, it is important to hold link-up statusof ethernet switch ports when the optical transmission line is switching. In this study, we developed the link-up
hold method, the control procedure for the photoelectric hybrid switch systems by using EtherCAT and OpenFlow
function. Furthermore, the change timing of the TOS (Type of Service) value of the IP packet not to cause packet
loss was clarified.
< Photoelectric hybrid SW control Algorithm>
A traffic engineering algorithm and a fast control plane technique for network controllers have been developed
to achieve effective traffic engineering for next-generation datacenter with disaggregation architecture. The main
results are as follows: (1) As a traffic engineering algorithm, we have investigated two approaches, service-driven
and data-driven, and a traffic engineering algorithm suitable for the photoelectronic hybrid switch system has
been developed to improve the execution time of large-scale distributed deep learning applications. (2) A fast
control plane technology has been developed. It is scalable up to 1000 racks and allows optical switches to beconfigured in 100 µs. (3) A model for describing the functionality and status of optical components has beendeveloped for resource management of the photoelectric hybrid switch system. Finally, the proposed network
controller that integrates the above functions has been demonstrated the effectiveness on a photoelectronic hybrid
switch system.
<Performance maximization of optical SW network architecture>
Next-generation computing is expected to have a wide range of applications, including various AI-related
services and cloud-related services. We developed an efficient optical switch network architecture that can be
optimized for various applications and computing environments including disaggregation type next-generation
data centers. In order to achieve the low power consumption, high performance, maximization of economic
efficiency, optimization is required according to the applications. Scalability (pay-as-you-grow) is also important
for the economical introduction of large-scale switches. We realized an optical switch architecture that canoptimize the modulation format, number of ports, space/wavelength switch function configuration. As for thefuture expandability, we have demonstrated that it can be expanded to more than 7,000 ports by the optical switchtransmission experiments using newly developed devices. Regarding the capacity, we developed new opticalswitch architectures utilizing space division multiplexing, ultra-wideband transmission, and ultra-high density
wavelength division multiplexing, and realized a switch capacity exceeding one petabit per second. Furthermore,
we proposed a method to greatly improve the latency characteristics of data centers and verified its effectiveness-4-

through the control network experiments.
<Optical ToR switch & Optical wavelength transmitter and receiver>To develop the Optical wavelength transceiver, the optical burst signal receivers in digital coherent opticalcommunication system are studied. Targeting fast wavelength switching, a Proportional-Integral-Differentialcontroller of a tunable laser is developed. As a result, the wavelength switching time of 100 µs is expected to beachieved. Moreover, an optical burst receiver is considered. By providing an intradyne coherent receiver withgain control voltage at the same time as wavelength switching, optical burst signal receiver is achieved. Opticalwavelength transceiver is fabricated by implementing the above technologies and Burst-mode multi-levelmodulation processor. Finally, Optical ToR switch with Optical wavelength transceiver, Electrical-switch
interface and EtherCAT, which is used as an external control interface, is prototyped and evaluated. Thewavelength switching time is less than 100 µs, and the error-free operation is achieved with a Forward Error
Correction in 400 Gbps mode. Also, the operation of Photoelectric hybrid switch incorporating this Optical ToR
switch has been demonstrated with an external control of EtherCAT.
<Burst-mode, multi-level-modulation processor>
Burst-mode, multi-level-modulation processor is one of the components of an optical wavelength transmitterand receiver. It is a digital signal processing circuit that generates a multi-level signal for generating a multi-level
coherent optical signal on the transmitter side and demodulates the received optical burst signal on the receiverside. We developed some prototypes of the burst-mode, multi-level-modulation processor step by step in order tosimultaneously realize optical multi-level modulation/demodulation that expands transmission capacity and highspeed response that can handle optical burst signals with short signal durations and non-uniform timings. In theevaluation using a final prototype chip, we achieved the target high-speed response time of 100 µs or less in bothtransmission speed modes of 200 Gbps and 400 Gbps. Furthermore, the final prototype chip was incorporated
into an optical wavelength transmitter and receiver, and through system verification, it was verified that it could
operate in an optoelectronic hybrid switch system, and burst-mode, multi-level-modulation processor technology
was established.
< Optical core SW>
We have designed and the implemented prototype equipment for the principle verification of the switchingsystem consisting of more than 1,000 I/O ports and having the capability of short switching time of less than 100µs. And also the functional basis of cooperative operation with other functional parts, namely the optical ToR
switch, the optical wavelength transmitter and receiver, and the SW controller was implemented. Following threepoints were regarded as important points: (1) Design from the viewpoint of optical signal transmission such as
optical level diagrams and optical signal-to-noise ratio diagrams. (2) Design from the viewpoint ofimplementation such as the total equipment size when fully implemented. (3) Design from the viewpoint ofcooperation with other functional parts. In addition, we have also verified the high-speed switching operation at
the optical physical layer utilizing the developed high-speed spatial switch and the high-speed wavelength tunable
laser.

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< International standardization>
We had two objectives on this activity. For the “system control program”, we conducted the open-source
strategy, and gave the presentation at the international conference. Source code can be downloaded through thespecific site. For the parts technologies, we keep those parts technology information secret rather than disclose
them through patent strategy.
<Photoelectric hybrid SW system verification>
A verification system by using a developed optical core switch, optical wavelength transmitters and receivers
and burst-mode, multi-level-modulation processors was bult to demonstrate the system functions. Transmission
line switching time less than 250 µs was achieved by cooperation control using EtherCAT. And it wasdemonstrated that there was not a packet loss when transmission line is switched. Furthermore, the demodulationfor 400 Gbps optical burst signal was showed by using the experimental boards that burst-mode, multi-levelmodulation processor was implemented.

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