“…[1][2][3][4][5][6][7][8] In addition, they also show features which cannot be implemented with plain waveguides, such as all-optical limiting, 1,9 all-optical switching, and bistability. 1,[10][11][12][13][14][15] This enhancement of the nonlinearity, however, happens at the cost of reduction of the signal bandwidth, which typically leads to a trade-off situation. 1,2 In practice, however, resonant structures such as ring resonators and photonic crystal resonators are much more critical to fabricate than simple waveguides and therefore suffer from additional loss mechanisms such as radiation and scattering loss.…”