Method and apparatus for radiant energy modulation in optical fibers
Spectral filter for integrated optics
Method for impressing gratings within fiber optics
Narrow-band wavelength selective optical coupler
Devices and methods for selectively tapping optical energy from an optical fibre
Optical fibre reflective diffraction grating devices
Variable-waveguide optical branching filter Patent #: 4874216
AbstractA variable light filtering arrangement includes at least one optical fiber section including a waveguiding core, and at least one permanent Bragg grating region in the optical fiber section. The grating region includes a plurality of grating elements constituted by periodic refractive index variations of a predetermined initial periodicity and cumulatively redirecting, of the light launched into the core for guided propagation therein, that having an axial wavelength within a narrow band around a central wavelength that is determined by the periodicity and refractive index variations of the grating elements. At least one of the periodicity and refractive index variations of the grating region is controlledly modified in such a manner as to temporarily change the central wavelength within a predetermined wavelength range.