Single-element optical wavelength bandpass filter formed in optical fiber or optical waveguide and method of manufacture thereof

摘要

An optical wavelength filter having one or more bands of transmission wavelengths of light, within a reflection spectrum of the filter, is formed using a section of an optical fiber (70) as an optical fiber grating. The optical fiber core (1) is configured with a periodically varying diffraction coefficient structure (3) formed such that the grating pitch continuously varies in a fixed direction, with that structure containing one or more regions of interruption (4, 5) of the continuous variation of pitch, whereby the bands of transmission wavelengths are respectively defined by these interruption regions.