Abstract
We demonstrate a flexible-bandwidth network testbed with a real-time, adaptive control plane that adjusts modulation format and spectrum-positioning to maintain quality of service (QoS) and high spectral efficiency. Here, low-speed supervisory channels and field-programmable gate arrays (FPGAs) enabled real-time impairment detection of high-speed flexible bandwidth channels (flexpaths). Using premeasured correlation data between the supervisory channel quality of transmission (QoT) and flexpath QoT, the control plane adapted flexpath spectral efficiency and spectral location based on link quality. Experimental demonstrations show a back-to-back link with a 360-Gb/s flexpath in which the control plane adapts to varying link optical signal to noise ratio (OSNR) by adjusting the flexpath's spectral efficiency (i.e., changing the flexpath modulation format) between binary phase-shift keying (BPSK), quaternary phase-shift keying (QPSK), and eight phase-shift keying (8PSK). This enables maintaining the data rate while using only the minimum necessary bandwidth and extending the OSNR range over which the bit error rate in the flexpath meets the quality of service (QoS) requirement (e.g. the forward error correction (FEC) limit). Further experimental demonstrations with two flexpaths show a control plane adapting to changes in OSNR on one link by changing the modulation format of the affected flexpath (220 Gb/s), and adjusting the spectral location of the other flexpath (120 Gb/s) to maintain a defragmented spectrum.
Highlights
Flexible bandwidth networking provides an effective way of scaling existing networks to more efficiently utilize available spectral resources [1]
Flexible bandwidth systems based on bandwidth scalable technologies such as optical arbitrary waveform generation (OAWG)/OAWM are capable of generating arbitrary bandwidth flexpaths, in which each flexpath can be in a different modulation format
We presented flexible bandwidth network testbed demonstrations of impairment awareness that rely on a commercial field-programmable gate arrays (FPGAs) and a 1.25 Gb/s supervisory channel to provide monitoring information for 360 Gb/s and 220 Gb/s flexpaths
Summary
Flexible bandwidth networking provides an effective way of scaling existing networks to more efficiently utilize available spectral resources [1]. If the QoT for a particular channel degrades below an acceptable threshold, the change in modulation format to a less spectrally efficient format would use more bandwidth, but has an increased resistance to the signal degradation This manuscript presents flexible bandwidth experimental testbed demonstrations using an adaptive control plane that adjusts flexpath modulation format in an effort to maintain data rate under conditions of varying link OSNR. This ensures minimization of the spectral efficiency for each flexpath while maintaining an acceptable BER.
Sign-in/Register to view highlights & summary Sign-in/Register to access full text options 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a call
