Compact and broadband polarization rotator on thin-film lithium niobate utilizing mode hybridization

. Numerically, the PR exhibits an insertion loss (IL) of 0.23 dB and an extinction ratio (ER) of 42 dB at 1550 nm, while its bandwidth for ER > 20 dB and IL < 1 dB exceeds 175 nm. The measurement result shows IL < 1 dB and ER > 19 dB in the wavelength range of 1490-1590 nm.