minimize Fresnel reflection from a perpendicularly cleaved fiber using a uniform fiber Bragg
grating (FBG) inscribed at the fiber end. By matching the reflectivity of an in-line FBG with the
reflectivity caused by the glass-air boundary, the FBG acts as a virtual boundary, which
provides destructive interference and suppresses Fresnel reflection. We achieved an anti-
reflection FBG with a return loss of more than 80 dB by ensuring that the product of the index …