title: Fabrication of a highly efficient core-mode blocker using a femtosecond laser ablation technique.
abstract: We present a method for the fabrication of a highly efficient core-mode blocker based on a laser micromachining technique. The process for the fabrication is as follows. A micron-sized crater is made by irradiation of an ultra-short pulse laser on the end face of a single-mode fiber, and then a defect that acts as a core-mode blocker is formed by splicing the cratered fiber with a normal fiber. The attenuation of the core mode was adjustable up to 25 dB according to the initial crater size and the splicing condition. An all-fiber acousto-optic tunable bandpass filter built with the core-mode blocker is also demonstrated, which exhibits a low insertion loss of 1.8 dB with non-resonance light suppression greater than 23 dB.
authors.affiliation: Department of Physics, Korea Advanced Institute of Science and Technology, Daejeon, 305-701, Korea. sdlim@kist.re.kr
authors.forename: Sun
authors.initials: S
authors.lastname: Do Lim
authors.forename: Jae Gu
authors.initials: JG
authors.lastname: Kim
authors.forename: Kwanil
authors.initials: K
authors.lastname: Lee
authors.forename: Sang Bae
authors.initials: SB
authors.lastname: Lee
authors.forename: Byoung Yoon
authors.initials: BY
authors.lastname: Kim