Abstract

We investigate a large-scale and fast optical circuit switch system that uses digital coherent technologies. The achievable port count is expanded by introducing colorless detection which eliminates channel selecting filters at receivers. Wavelength selection is performed using a shared local oscillator (LO) bank, which is configured by combining a multi-wavelength optical source with Silicon-photonic tunable filters (TFs). Microsecond switching times are realized with the thermo-optic effect available with the Silicon-photonic TF. Design optimization of the proposed system handles complex level of freedom, i.e., available wavelength number, space switch port count, optical amplifier location and gain, and device loss. In addition, colorless coherent detection induces penalties, which further complicates switch scale assessment. In this paper, we develop a simulator to clarify how those parameters affect switch performance; the switch throughput is maximized with consideration of the degradation stemming from colorless detection. The design performance accurately matches results measured in various system scenarios. A dual-carrier 256-Gb/s DP-QPSK experiment successfully demonstrates a 1,856 $ \times $ 1,856 optical switch system with switching time under 3.52 μs. The resulting total throughput is 441 Tb/s assuming 7%-overhead HD-FEC. To the best of our knowledge, this is the first demonstration of 400-Tbps class large bandwidth optical switches that use TFs as wavelength selective devices for coherent detection.

Design and verification of a LO bank enabled by fixed-wavelength lasers and fast tunable silicon ring filters for creating large scale optical switches

Ryosuke Matsumoto, Ryotaro Konoike, Hiroyuki Matsuura, Keijiro Suzuki, Takashi Inoue, Yojiro Mori, Kazuhiro Ikeda, Shu Namiki, and Ken-ichi Sato
Opt. Express 29(24) 39930-39945 (2021)

Optical switching will innovate intra data center networks [Invited Tutorial]

Ken-ichi Sato
J. Opt. Commun. Netw. 16(1) A1-A23 (2024)

Design and Verification of Large-Scale Optical Circuit Switch Using ULCF AWGs for Datacenter Application

H. Nagai, Y. Mori, H. Hasegawa, and K. Sato
J. Opt. Commun. Netw. 10(7) B82-B89 (2018)

Experimental verification of highly scalable OXC that consists of subsystem-modular express-switch part and multicast-switch-based add/drop part enabling total throughput of 314 Tbps

Shoichi Takashina, Hiroto Ishida, Masaki Niwa, Yojiro Mori, Hiroshi Hasegawa, Ken-ichi Sato, and Toshio Watanabe
Opt. Express 23(11) 14796-14805 (2015)

High-port-count optical circuit switches for intra-datacenter networks [Invited Tutorial]

Yojiro Mori and Ken-Ichi Sato
J. Opt. Commun. Netw. 13(8) D43-D52 (2021)