Multiheterodyne detection for self-referenced characterization of complex arbitrary waveforms from largely detuned optical frequency combs

Abstract

Recently, it has been demonstrated that by considering a larger portion of the RF comb, a self-referenced measurement of each optical comb can be recovered, thus eliminating the need for a known reference with flat phase. In this manuscript, a more general form of this technique is explored, in which the mode spacings of the two unknown comb sources are detuned from each other by a factor of two or greater. This is a case of interest, seeing as how arbitrary waveforms generated from spectral modulation of OFCs which one might wish to characterize regularly exceed 10's of GHz rates, whereas the self-referenced, carrier-envelope offset stabilized sources which provide absolute knowledge of the optical frequencies involved in the multiheterodyne process are most commonly found in the sub-GHz repetition rate regime.