Devices, methods and systems for removing unwanted tissue from within a patient's vasculature system are provided. Specifically, a laser ablation catheter having a tip with an open, arched-shaped cross section is described. The cross section of the tip enhances the catheter's ability to ablate, separate, and/or dilate the various layers within a patient's vasculature, thereby facilitating the removal undesirable lesions and fibrous tissue within a patient's vasculature.