All-fiber acousto-optic tunable filter

Abstract

This invention relates to an all-fiber acousto-optic tunable wavelength filter which is useful in optical communications or optical fiber sensor systems. The present invention provides an all-fiber acousto- optic tunable filter, comprising: a length of optical fiber for propagating optical waves; a first mode converting means for selectively converting a core mode of the optical wave propagating in said optical fiber into a cladding mode by means of acoustic wave, depending on the wavelength of the optical wave; and a mode selecting means for selecting one or more mode among the core modes and cladding modes. In the embodiment of the invention, the mode selecting means may be configured to be a length of optical fiber whose jacket is partially stripped and a flexural acoustic wave generator to which electrical signal with a plurality of frequency components is applied. According to the invention, the wavelength filters provides a wide tuning range and can electrically control its filtering feature.