Long-period fiber grating
= Long-period fiber grating
{wiki=Long-period_fiber_grating}
Long-period fiber gratings (LPFGs) are specialized types of optical fiber devices that are used to selectively couple light between the guided modes of the fiber and radiative modes or cladding modes. These gratings are created by periodically refracting the core refractive index of optical fibers, typically through techniques like ultraviolet (UV) light exposure or by using electric field poling.