  We present a new approach to engineering broadband sources of entangled
photon pairs for quantum interferometry. The source is based on
quasi-phase-matched spontaneous parametric down conversion in a titanium
diffused periodically poled lithium niobate waveguide with a strongly-chirped
poling period. The proposed non-standard asymmetric poling mitigates phase
distortions associated with the process of chirping. Asymmetric poling
significantly broadens the entangled source bandwidth while preserving high
visibility quantum interferometric sensing.
