Gain Effect on Scalable Energy-Proportional SOA-Based Optical Space Switches

Energy-proportional optical interconnections are enabled by semiconductor optical amplifiers (SOAs) remaining off (or idle) when not routing data. In this letter, the physical layer scalability of SOA-based optical space switches configured with different gain and loss is assessed using an experimental recirculating loop. Results show that for a gain/loss configuration of 13.0 dB, optical multichannel packets successfully propagate through a series of 14 SOAs with a bit-error-rate <; 10^-9, which indicates that a single-stage space switch can scale up to 10⁹ ports. Scalability improves for lower gain/loss configuration at the cost of more SOAs per routing path. As expected, scalability is limited by cross-gain modulation and optical signal-to-noise ratio degradation, but their detrimental impact depends on the architecture configuration.