Extended Data Table 1 Comparison to previous works in combing a PhC and a microring. Previous works fall into two categories, referred to as photonic crystal rings (PhCRs) and photonic crystal disk/ring resonators (PCDRs/PCRRs) in the literature, whose structures are based on microrings and 2D PhCs, respectively. The original work in a PhCR and a PCRR are in bold. PhCRs typically support multiple modes in a WGM fashion, and therefore have SRs listed. PCRRs only have single or few modes and SRs are not analyzed. Although not listed here, PCRRs typically have much smaller mode volumes than PhCRs. We note that reference ¹⁵ has Q and SR reported in different devices. Overall, we find that the MPhCR has the highest n_g/α, which is an important metric for slow light application (see Methods

From: High-Q slow light and its localization in a photonic crystal microring