Impairment-aware routing in translucent spectrum-sliced elastic optical path networks

Spectrum-sliced elastic optical path (SLICE) technology offers a more flexible bandwidth allocation in optical networks than wavelength division multiplexing. It allows different connections to be served via different modulation formats. However, as with any optical network, the optical signal may be susceptible to signal impairments, especially when the signal traverses over long distances. The degree of impairment may differ per modulation type, but in any case must be taken into account. If impairment levels get too high, the signal needs to be regenerated by regenerators placed selectively (due to cost considerations) inside the network. In this paper we study the impairment-aware dynamic routing and subcarrier allocation problem in translucent SLICE networks. We propose an impairment-aware routing algorithm that tries to balance traffic flows evenly across the network to reduce the blocking probability. We consider two cases, namely (1) a modulation will be selected that is used by the entire connection, and (2) the modulation can be changed during regeneration at regenerator nodes on the path.