Computing such as cloud services and big data analytics is built on an infrastructure based on electrical switches. However, the technology for miniaturizing the semiconductors that support electrical switches is beginning to show limitations, so significant improvement in energy efficiency cannot be expected. With the future spread of 5G mobile networks, switch technology that achieves efficient processing not only for data centers but also in the edge computing field will be needed.

Silicon photonics optical switches (optical switches) exhibit dramatically higher energy efficiency than electrical switches, so they are useful in dynamic reconfiguration where the transfer paths for large-volume data are switched at high speed such as in the optical network and computing fields, and are expected to be a key technology for reducing the load on electrical switches. Small and high-speed optical switches are attracting increasing attention worldwide for potential application to next-generation data centers and supercomputers that require a large scale of around 100,000 ports, and AIST has previously confirmed scalability equivalent to 512 ports and 1.5 million Gbps with a Clos configuration. However, the impact of crosstalk between ports (crosstalk) increases together with the scale, so the number of ports and energy efficiency achievable in a Clos configuration using optical switches had not yet been clarified.

Researchers in AIST demonstrated developed that the world's largest total optical switch capacity of 125 million Gbps can be achieved in a 131,072 port optical switch network. This corresponds to the capacity to transmit the data of 600,000 or more Blu-ray discs per second.

This study used the world's largest capacity 32×32 port optical switch developed by AIST to conduct a circular transmission experiment in which a wideband optical signal was transmitted through the same optical switch nine times. Furthermore, the behavior of crosstalk in the optical switch was statistically analyzed, and a general theory for maximizing the number of optical switch ports was established. These results satisfy the requirements of optical switches demanded by next-generation data centers and supercomputers (figure), and this technology will contribute to high-capacity, low-latency next-generation information infrastructure.