Routing is essential to the seamless operation of an optical network. In this paper, we develop a novel routing algorithm specially tailored for optical networks. It uses machine learning methods to predict the feasibility of a particular route and depending on the prediction outcome makes the decision on whether to admit or reject the specific route. The machine learning model for feasibility prediction is created using data gathered via the control plane from a real telecoms network. The results obtained show the superiority of the proposed routing algorithm when compared with the standard approach.