Abstract: An optical amplification system is described which comprises an optical amplifier and an optical filter. The gain of the optical amplifier is changeable to different gain values. For every one of the gain values, a wavelength-dependent gain curve exists. At least for one of the gain values, the gain curve varies over the wavelength. An apodized long-period grating (LPG) is used as the optical filter. The apodized LPG provides at least one wavelength-dependent attenuation curve which compensates the gain curve varying over the wavelength.

Abstract: The present invention relates to the field of optical fiber telecommunications. More specifically, the subject of the invention is a slanted Bragg grating optical fiber and a process for manufacturing such a fiber. The slanted Bragg grating optical fiber of longitudinal axis Z has slanted Bragg gratings photowritten in said fiber and having refractive index modulations along said axis Z, inclined at a same writing angle with respect to a normal plane to said axis Z and defining planes called writing planes forming the same angle than the writing angle with said normal plane, each writing plane forming with others writing planes specific angles called angles of rotation about said axis Z.

Abstract: A tuneable optical fibre comprising a long-period Bragg grating (5) written in a portion of an optical waveguide (10) comprising a core and an optical cladding (11), characterised in that the portion of the waveguide comprising the grating (5) is at least partially immersed in an external environment consisting of two distinct sections, a first section (1) whose refractive index is higher than that of the optical cladding (11) and a second section (2) whose refractive index is lower than that of the optical cladding (11), the long-period grating being at least partially immersed in one of the said sections so as to almost independently tune the wavelength and/or the contrast of the spectral response of the filter.

Abstract: A tuneable optical fibre comprising a long-period Bragg grating (5) written in a portion of an optical waveguide (10) comprising a core and an optical cladding (11), characterised in that the portion of the waveguide comprising the grating (5) is at least partially immersed in an external environment consisting of two distinct sections, a first section (1) whose refractive index is higher than that of the optical cladding (11) and a second section (2) whose refractive index is lower than that of the optical cladding (11), the long-period grating being at least partially immersed in one of the said sections so as to almost independently tune the wavelength and/or the contrast of the spectral response of the filter.

Abstract: An optical filter includes a coupler having n output branches and an input branch receiving an input signal whose spectrum comprises a comb of wavelengths periodically spaced by a spacing eP. Each of the n output branches is coupled to a waveguide including two or more cascaded copropagated coupling components. Each of the n branches produces an output signal whose spectrum comprises a comb of wavelengths periodically spaced by a spacing equal to n times the spacing eP. Each of the n output signal spectra is complementary to the others.

Abstract: The present invention relates to the field of optical fiber telecommunications. More specifically, the subject of the invention is a slanted Bragg grating optical fiber and a process for manufacturing such a fiber. The slanted Bragg grating optical fiber of longitudinal axis Z has slanted Bragg gratings photowritten in said fiber and having refractive index modulations along said axis Z, inclined at a same writing angle with respect to a normal plane to said axis Z and defining planes called writing planes forming the same angle than the writing angle with said normal plane, each writing plane forming with others writing planes specific angles called angles of rotation about said axis Z.