Erratum: Broadband adiabatic polarization rotator-splitter based on a lithium niobate on insulator platform (Photon. Res. (2021) 9 (2319-2324) DOI: 10.1364/PRJ.432906)

This publisher's note reports corrections to the text in Photon. Res. 9, 2319 (2021). The second paragraph in Section 2 of this article was corrected as follows. In the polarization rotator (Step I), the LN rib waveguide adiabatically widens from a top width of 1.2 to 3.6 μm via a linear taper, such that the effective index of the second-order TE (TE₁) mode surpasses that of the fundamental TM (TM₀) mode [Fig. 1(c)]. The partially etched structure breaks the vertical symmetry of the waveguide and enables a substantial avoided crossing between the two modes (Δn_eff = 0.019) at a waveguide top width of 2.12 μm as shown in Fig. 1(c). As a result, the input TM₀ mode is converted first to a hybridized mode between TM₀ and TE₁ [inset of Fig. 1(c)] and finally to the TE₁ mode. While the input TM₀ mode is rotated and converted into TE₁ mode, the polarization state of the input TE₀ mode remains unchanged during Step I, since it stays the highest-index mode throughout the tapered structure [blue curve in Fig. 1(c)]. The text in bold was incorrect in the original published version, and the article was corrected online on 7 December 2021 [1]. ^†These authors contributed equally to the paper.