Control plane techniques are very important for optical networks since they can enable dynamic lightpath provisioning and restoration, improve the network intelligence, and greatly reduce the processing latency and operational expenditure. In recent years, there have been great progresses in this area, ranged from the traditional generalized multi-protocol label switching (GMPLS) to a path computation element (PCE)/GMPLS-based architecture. The latest studies have focused on an OpenFlow-based control plane for optical networks, which is also known as software-defined networking. In this paper, we review our recent research activities related to the GMPLS-based, PCE/GMPLS-based, and OpenFlow-based control planes for a translucent wavelength switched optical network (WSON). We present enabling techniques for each control plane, and we summarize their advantages and disadvantages.