(a) Energy density of the phase-matched guided modes at ω₀ (TE₀₀ and TM₀₀) and 2ω₀ (TE_02,SH). (b) n_eff vs. w diagram of type-I (red marker) and type-II (blue marker) modal PM. (c) SHG efficiency as a function of the angle θ between the propagation direction and the [100] axis. (d) Effective index n_eff, (e) group velocity β₁, and (f) GVD β₂ for the TE_00,FF (blue dashed line), TM_00,FF (blue pointed line) and TE_02,SH modes (red dashed line). In (d, e, f) the colored arrows indicate the corresponding x-axis.