Degenerate four-wave mixing in a silica hollow bottle-like microresonator.

A hollow, bottle-like microresonator (BLMR) was fabricated from a microcapillary with a nearly parabolic profile. From simulations at 1.55 µm the fundamental bottle mode is shown to be in the anomalous dispersion regime, while the conventional whispering gallery mode, confined to the center of the BLMR, is in the normal dispersion regime. Therefore, we have experimentally shown that, for a BLMR with a diameter of 102 um, degenerate four-wave mixing can only be observed by judicious selection of the tapered fiber coupling position. Dispersion tuning in such a system is also briefly discussed theoretically. BLMRs are promising devices for the implementation of sparsely distributed, widely spanned frequency combs at the telecommunications C-band.