Experimental assessment of a scalable and flow-controlled optical switch system for flat datacenter networks

We propose and demonstrate an optical flat data center network based on scalable optical switch system with optical flow control. Experimental evaluation of the system at data rate of 40 Gb/s includes a 4×4 optical switch with highly distributed control for port-count independent nanosecond reconfiguration time for low latency operation. The hardware flow control at the optical level allows fast retransmission control of the electrical buffered packets at the edge nodes preventing the need of optical buffers. Moreover, this makes a dedicated flow control network redundant, which effectively reduces system complexity and power consumption. Dynamic switch operation reported 300 ns minimum end-to-end latency (including 25 m transmission link) and <; 10^-6 packet loss for 0.4 load with buffer size of 16 packets.