From a Norman French name, Raulf, a contracted form of the Germanic personal name Radulf, derived from rād ‘counsel’ + wulf ‘wolf’. The spelling with -ph is due to classical influence in the 18th century.
German and Jewish (Ashkenazic): from the personal name Gottlieb. As a German personal name this is for the most part a translation of Greek Theophilos (‘one who loves God’) that became very popular in the 17th and 18th centuries with the rise of the Pietist movement. Among German Jews, it existed, independently from German Christians, since the Middle Ages.