Abstract: A method and apparatus for tunable on-fiber Bragg gratings for DWDM and other applications on a small section of the core of single mode communication of an optical fiber. The method comprises etching most of the cladding on a small section of the fiber; coating the etched portion with a metallic electrode material and then with a layer of an electrooptic material; coating the electrooptic material with a photoresist; producing the Bragg grating pattern using a holographic process or on-axis interferometry; dissolving the non-exposed photoresist,; etching the grating pattern into the electrooptic material, and coating the Bragg gratings with a metallic material constructing the outer electrode. The presence of an electric signal on the electrodes will change the optical properties of the electrooptic material, as well as the diffraction/reflection properties of the Bragg gratings.

Abstract: Application of a communication signal, RF (radio frequency) or microwave signal to a modified optical fiber for modulating or switching-off the optical signal propagating within the optical fiber. The passive cladding material of an ordinary optical fiber is removed from a small region and the fiber is coated with one or more layers of coated materials including a layer of electrooptic material surrounding the fiber core. A microwave cavity is positioned around the modified fiber where the optical fiber is passing through the cavity in the direction of the cavity main axis to provide a modulating microwave electromagnetic field applied to the electrooptic material. A communication signal applied to the microwave cavity will result in optical modulation so that the modulated intensity and phase of the optical signal at the receiving end of the fiber can be detected, and demodulation of the signal can be achieved.

Abstract: Application of a communication signal, RF (radio frequency) or microwave signal to a modified optical fiber for modulating or switching-off the optical signal propagating within the optical fiber. The passive cladding material of an ordinary optical fiber is removed from a small region and replaced with active multilayer materials including at least three layers of cladding surrounding the core. These layers are the inner metallic electrode coated on the surface of the optical fiber core, the electrooptic active material layer placed on the top of the inner electrode, and the outer metallic electrode coated on the top of the electrooptic material. A communication signal applied to the electrodes will result in optical modulation so that the modulated intensity and phase of the optical signal at the receiving end of the fiber can be detected, and demodulation of the signal can be achieved.

Abstract: An on-fiber tunable coupler and switch for communication systems. Two optical fibers are modified by replacing passive cladding with at least an inner metallic electrode, an electrooptic material layer on the inner electrode, and an outer metallic electrode on the electrooptic material. The optical fibers are positioned close to each other. More layers can be coated between any of these layers to improve the interface properties or reflectivity. The presence of an electric signal, will change the optical properties of the modified cladding, as will the propagation characteristics of the optical signal within one fiber core. This will permit tunable coupling of the signal from the first fiber core to the second fiber core(s). The coupling coefficient between the first and the second fiber(s) is adjustable. Switch-off the signal output from the first fiber to the second fiber is achieved at 100% coupling ratio.