We have demonstrated a method that efficiently transfers the power fro
m a single-frequency laser into a wideband frequency comb. The comb wa
s produced by a 2.7-GHz electro-optic modulator in a resonant optical
cavity. A coupled cavity technique was used to transfer 8.5% of the la
ser power into a comb with a span of 400 modes, or more than 1 THz.