Elastic Optical Interface With Variable Baudrate: Architecture and Proof-of-Concept

Abstract

Varying the symbol rate is an alternative or complementary approach to varying the modulation format or the channel spacing, in order to turn optical networks into elastic networks. We propose to allocate just-enough bandwidth for each optical connection by adjusting the symbol rate such that penalty originating from long cascades of optical filters is contained. This helps reducing overprovisioning for lightpaths where full capacity is not needed, by (i) eliminating unnecessary regenerators and (ii) reducing the power consumption of terminals, when the clock rate of electronics is reduced along with the Baud rate. We propose a novel architecture for an elastic optical interface combining a variable bitrate transceiver, paired with an elastic aggregation stage, with software-defined control. We then report a real-time FPGA-based prototype, delivering flexible transport frames to be sent with a PDM-QPSK modulation format. We interconnect this prototype with a commercial OTN switch and a centralized controller. We demonstrate fast and hitless reconfiguration of the interface and measure the reconfiguration time of hardware logic (<450µs) as well as end-to-end control and data plane (<0.9s).

Joint power-efficient traffic shaping and service provisioning for metro elastic optical networks

“…The time duration of each stage has its limiting factors and cannot be reduced below a certain bound. In view of the demonstrated hitless transponders and proposed fast SDN-based control signalling methods [10], [11], the allocation stage usually has the dominant time duration, which is limited by the computational complexity of the resource allocation algorithm [23].…”

Dynamic realization of miscellaneous profile services in elastic optical networks using spectrum partitioning

“…Hitless spectrum reallocation is well supported in the literature by proposing node structure [14] and practical methods [15,16]. Also hitless BVTs with zero loss of data in reconfiguration are presented and proved experimentally in [17,18].…”

“…from (18). In this work, we split slots among partitions according to their bin-sizes and contribution probability.…”

Flexible and lossless baud-rate switching for 4-time slots Nyquist OTDM signals using wavelength selective switch

“…Therefore, the elastic optical network efficiently utilizes limited optical frequency resources and realizes ultra large capacity communication exceeding 1 Tbaud/s that usually requires a wide bandwidth. In addition, the use of flexible symbol rate is advantageous to accommodate various modulation schemes and different baud rate signals [4,5]. A Wavelength Selective Switch (WSS) [6,7,8] is one of promising devices for handling flexi-grid add-drop WDM channels [9,10,11] and a baud rate variable transponder [12,13,14].…”