Multiplexing of Asynchronous and Independent ASK and PSK Transmissions in SDN-Controlled Intra-Data Center Network

An intra-data center architecture employing a cost-effective multi-level transmission scheme is presented. Unlike related previous works, the proposed scheme enables the optical multiplexing of two asynchronous and independent optical streams into an eight-amplitude phase-shift keying signal. The scheme is particularly suitable for intra-data center scenarios, where cost-effective solutions have to guarantee adequate bandwidth flexibility. The proposed transmitter successfully multiplexes two data streams, namely a 40 Gb/s differential quadrature phase-shift keying signal and a 10 Gb/s on-off keying one, coming from two separate (and not synchronized) apparatus. The experimental implementation, including two non-coherent receivers, reveals satisfactory performance ensuring a correct functionality (bit error rate <;10 ^-9) for an optical signal-to-noise ratio of about 31 dB. The design of an intra-data center switch architecture encompassing the proposed transmission scheme is then presented. Additionally, the switch includes a specifically defined Open Flow control enabling bandwidth flexibility according to application service requirements. The overall solution has been successfully implemented and demonstrated in an experimental testbed including traffic tributaries provided through off-the-shelf network elements. The overall configuration is successfully completed within a few milliseconds only.