Novel routing algorithm for transparent optical networks based on noise figure and amplifier saturation

We propose and demonstrate a novel dynamic routing algorithm for transparent optical networks based on physical layer impairments such as amplifier noise accumulation, amplifier gain saturation, wavelength dependent gain and losses along lightpaths. The metrics of our algorithm is based on the calculation of the noise figure using the well known formulation for cascade of elements in lightpaths. We assume no wavelength conversion capabilities in our network and we assign wavelengths using a first fit algorithm. For a given call, our algorithm assigns the first available wavelength and calculates the best route (minimum noise figure). Upon the calculation of the noise figure of the lightpath, we obtain the bit error rate (BER). Our algorithm blocks a call if there is no wavelength available or if the BER for the available wavelength is above a given level, which guarantees a pre-defined quality-of-service for the network operation. We present simulation results of dynamic traffic in a hypothetical meshed network in terms of blocking probabilities as a function of network load and amplifier characteristics. We show that our algorithm outperforms the traditional shortest path routing algorithm.