Hollow-core photonic crystal fiber based broadband radiation generator

A broadband radiation source device configured for generating broadband output radiation upon receiving substantially linearly polarized input radiation, the source device including: a hollow-core photonic crystal fiber; at least a first polarization element operable to impose a substantially circular or elliptical polarization on the input radiation prior to being received by the hollow-core photonic crystal fiber; and a second polarization element operable in combination with the first polarization element to impose a substantially elliptical polarization on the input radiation, wherein the second polarization element and the first polarization element are oriented such that the elliptical polarization compensates at least partially for birefringence of the hollow-core photonic crystal fiber.