This paper discusses the issue of providing basic QoS in optical burst-switched WDM networks. As in WDM networks, end-to-end connection demands are dynamic routes, it changes the state according to the current network traffic status. In order to improve the basic QoS, load balancing technique for lightpath establishment in Optical WDM Networks has been proposed. This approach contains three phases; initially the network's traffic is predicted with Hidden Markov Model (HMM). In the second phase wavelength ordering technique is implemented where the crosstalk in the network is reduced. In the final phase an objective function based on GRASP is considered for the predicted traffic load from phase-1. Through this approach, it is shown in this paper that the Quality of service (QoS) in the optical WDM network can be improved in terms of delay, throughput and blocking probability. © 2014 IEEE.