  While being invented for precision measurement of single atomic transitions,
frequency combs have also become a versatile tool for broadband spectroscopy in
the last years. In this paper we present a novel and simple approach for
broadband spectroscopy, combining the accuracy of an optical fiber-laser-based
frequency comb with the ease-of-use of a tunable external cavity diode laser.
This scheme enables broadband and fast spectroscopy of microresonator modes and
allows for precise measurements of their dispersion, which is an important
precondition for broadband optical frequency comb generation that has recently
been demonstrated in these devices. Moreover, we find excellent agreement of
measured microresonator dispersion with predicted values from finite element
simulations and we show that tailoring microresonator dispersion can be
achieved by adjusting their geometrical properties.
