Characterizing pump line phase offset of a single-soliton Kerr comb by dual comb interferometry

Abstract

We experimentally demonstrate phase retrieval of a single-soliton Kerr comb using electric field cross-correlation implemented via dual-comb interferometry. The phase profile of the Kerr comb is acquired through the heterodyne beat between the Kerr comb and a reference electro-optical comb with a pre-characterized phase profile. The soliton Kerr comb has a nearly flat phase profile, and the pump line is observed to show a phase offset which depends on the pumping parameters. The experimental results are in agreement with numerical simulations. Our all-linear approach enables rapid measurements (3.2 µs) with low input power (20 µW).

Differential phase reconstruction of microcombs

“…As a result, the spectral phase measurement is limited to the gain bandwidth of the amplifier or the bandwidth of the pulse shaper, whichever is narrower. An alternative diagnostic tool using dual comb interferometry was reported in [12,13]. This is a linear technique, first proposed in the context of fre-quency comb complex measurements in [14], which can also enable extremely fast acquisition rates [15].…”