Hollow-core optical fiber based radiation source

A radiation source including: a hollow core optical fiber having a body having a hollow core for confining a working medium, the hollow core optical fiber being operable to receive pulsed pump radiation such that the received pulsed pump radiation propagates through the hollow core from an input end to an output end of the hollow core optical fiber, wherein one or more source parameters of the radiation source are configured such that the pulsed pump radiation undergoes a soliton self-compression process so as to change a spectrum of the pulsed pump radiation to form output radiation; and at least one dispersion control mechanism being operable to change dispersion characteristics in a first portion of the optical fiber so as to spectrally shift a dispersive wave generated in the soliton self-compression process.