title: Tunable multimode-interference bandpass fiber filter.
abstract: We report on a wavelength-tunable filter based on multimode interference (MMI) effects. A typical MMI filter consists of a multimode fiber (MMF) spliced between two single-mode fibers (SMF). The peak wavelength response of the filter exhibits a linear dependence when the length of the MMF is modified. Therefore a capillary tube filled with refractive-index-matching liquid is used to effectively increase the length of the MMF, and thus wavelength tuning is achieved. Using this filter a ring-based tunable erbium-doped fiber laser is demonstrated with a tunability of 30 nm, covering the full C-band.
authors.affiliation: Photonics and Optical Physics Laboratory, Optics Department, Instituto Nacional de Astrofísica,Optica y Electrónica, Tonantzintla, Puebla 72000, Mexico.
authors.forename: J E
authors.initials: JE
authors.lastname: Antonio-Lopez
authors.forename: A
authors.initials: A
authors.lastname: Castillo-Guzman
authors.forename: D A
authors.initials: DA
authors.lastname: May-Arrioja
authors.forename: R
authors.initials: R
authors.lastname: Selvas-Aguilar
authors.forename: P
authors.initials: P
authors.lastname: Likamwa