This paper proposes an efficient framework for deterministic service guarantees in slot-based optical networks. The framework uses the combination of a control plane and a data plane to solve the complex problem of capacity allocation, slot-matching and traffic scheduling. The control plane implements admission control and capacity allocation to source-destination node pairs and the data plane handles traffic aggregation, buffering, and scheduling. We propose an efficient algorithm in the control plane for slot collision-resolution. In the data plane, we present a comprehensive aggregation and scheduling mechanism that realizes Service Curves assurance. We use the Time-Domain Wavelength Interleaved Network (TWIN) architecture for the proof of concept and conduct extensive simulations to assess the performance of the algorithm and scheduling mechanism.