In this paper, we present a study of integrated optical delay lines (DLs) for application in optical time-division multiplexers. The investigated DLs are formed by spirally folded waveguides. The components were designed in a generic approach and fabricated in multi-project wafer runs on an InP-based platform. The design process and rules, together with characterization results of test structures, are discussed. Static and dynamic measurements were performed for verification of the DLs' performance in the wavelength and time domain. Additionally, a comparison between the simulation and characterization results is given, which confirms good agreement between measured and designed values.