Increasing volume, dynamism, and diversity of access traffic have complicated the challenging problem of dynamic resource allocation in passive optical networks. We introduce a general scheduling procedure for passive optical networks, which optimizes a desired performance metric for an arbitrary set of operational constraints. The proposed scheduling has a fast and causal iterative implementation, where each iteration involves a local optimization problem followed by a recursive update of some status information. The generality of the platform enables a proper description of the diverse quality of service requirements, while its low computational complexity makes agile tracking of the network dynamism possible. To demonstrate its versatility and generality, the applications of the scheme for service-differentiated dynamic bandwidth allocation in time- and wavelength-division-multiplexed passive optical networks are discussed. To further reduce the computational complexity, a closed-form solution of the involved optimization in each iteration of the scheduling is derived. We directly incorporate transmission delay in the scheduling and show how the consumed power is traded for the tolerable amount of transmission delay. Furthermore, a 50% power efficiency improvement is reported by exploiting the inherent service diversity among subscribers. The impact of service prioritization, finite buffer length, and packet drops on the power efficiency of the scheme are also investigated
