which highlights the nonlinearity of the LP linewidth. Note that Eq. 33 recovers Eq. 32 for Θ N → π/2, and Eq. 31 for Θ N → π/4. Remarkably, it well captures the behavior of LP linewidth for π/4 < Θ N < π/2, as shown by Rury and co-workers . However, Eq. 33 does not recover Eq. 32 for the limit of Θ N → 0 (with |C| 2 → 1 and |X| 2 → 0) and is unbounded, which leads to a severe overestimation of the LP linewidth for 0 < Θ N < π/4. To solve this problem, we propose the following modification to Eq. 33 as follows