Wavelength selective variable reflector

An arrangement comprising an optical waveguide adapted to receive an optical signal which derives an evanescent field, a grating, an electro-optic material arranged adjacent the grating, a housing assembly, an input connector and an output connector, the electro-optic material having a refractive index which can be varied by applying an electric field to the material so as to control how the grating interacts with the evanescent field of the optical signal, the grating having a spatial period that increases gradually along a length of the grating.

An arrangement comprising an optical waveguide adapted to receive an optical signal which derives an evanescent field, a grating and an electro-optic material arranged adjacent the grating, the electro-optic material having a refractive index which can be varied by applying an electric field to the material so as to control how the grating interacts with the evanescent field of the optical signal, the grating having a spatial period that increases gradually along a length of the grating;

• wherein the electro-optic material comprises quartz.

An optical fiber, having a core and a cladding with a portion of the fiber etched to remove part of its cladding, the etched portion having been replaced with liquid crystal material and sandwiched between two substrates including an upper substrate and a lower substrate, an inner surface of the upper substrate being deposited with lines of electrodes for applying an electric field to a selectable region of the liquid crystal material, an inner surface of the lower substrate being etched with a Chirp grating and covered with a thin electrode, the Chirp grating having a spatial period that increases gradually along its length, the liquid crystal material having a property that when there is no electric field, the refractive index of the liquid crystal is less than or equal to the cladding's, and when electric field is applied, the liquid crystal re-orients itself and its refractive index increases higher than the cladding's.

An arrangement comprising an optical waveguide adapted to receive an optical signal which derives an evanescent field, a grating and an electro-optic material arranged adjacent the grating, the electro-optic material having a refractive index which can be varied by applying an electric field to the material so as to control how the grating interacts with the evanescent field of the optical signal, the grating having a spatial period that increases gradually along a length of the grating;

• wherein the arrangement is adapted to function as a wavelength selectable variable optical attenuator.

An arrangement comprising an optical waveguide adapted to receive an optical signal which derives an evanescent field, a Chirp grating and an electro-optic material arranged adjacent the Chirp grating, the electro-optic material having a refractive index which can be varied by applying an electric field to the material so as to control how the Chirp grating interacts with the evanescent field of the optical signal;

• wherein the Chirp grating has a spatial periodicity which increases along a length of the Chirp grating from ΛA to ΛB, where ΛA=λA/(2 neff), and ΛB=λB/(2 neff), and λA to λB is an operational wavelength range of the arrangement.