Mode-locked lasers with a dispersive cavity whose wavelengths can be tuned by changing either cavity length or modulation frequency, are promising to generate single- or multi-wavelength and wavelength-tunable optical short pulses. The transient states of wavelength tuning in such lasers, which may introduce significant timing and amplitude jitters, is undesirable for applications that require fast wavelength switching or sweeping. In this paper, we numerically and experimentally study the transient states of wavelength tuning in dispersion-tuned mode-locked lasers. The restriction on the tuning step of cavity length or modulation frequency for wavelength tuning to achieve an acceptable pulse performance is obtained.© (2010) COPYRIGHT SPIE--The International Society for Optical Engineering. Downloading of the abstract is permitted for personal use only.