Abstract: A method of fabricating a glass body that includes a multiplicity of constituents, at least one of which is a dopant (e.g., a rare-earth element) having a low vapor pressure (LVP) precursor includes the steps of: (a) generating an aerosol from the LVP precursor; (b) separately generating vapors of the other constituents; (c) convecting the aerosol and vapors to deposition system including a substrate; and (d) forming at least one doped layer on a surface of the substrate. In one embodiment, the method also includes filtering the aerosol so as to remove aerosol particles outside of a particular range of sizes. Also described is a unique aerosol generator that is particularly useful in generating aerosols of rare-earth dopants. Particular embodiments directed to the fabrication of Yb-doped optical fibers are described.

Abstract: A method of fabricating a glass body that includes a multiplicity of constituents, at least one of which is a dopant (e.g., a rare-earth element) having a low vapor pressure (LVP) precursor comprises the steps of: (a) generating an aerosol from the LVP precursor; (b) separately generating vapors of the other constituents; (c) convecting the aerosol and vapors to deposition system including a substrate; and (d) forming at least one doped layer on a surface of the substrate. In one embodiment, the method also includes filtering the aerosol so as to remove aerosol particles outside of a particular range of sizes. Also described is a unique aerosol generator that is particularly useful in generating aerosols of rare-earth dopants. Particular embodiments directed to the fabrication of Yb-doped optical fibers are described.

Abstract: A method of fabricating a glass body that includes a multiplicity of constituents, at least one of which is a dopant (e.g., a rare-earth element) having a low vapor pressure (LVP) precursor comprises the steps of: (a) generating an aerosol from the LVP precursor; (b) separately generating vapors of the other constituents; (c) convecting the aerosol and vapors to deposition system including a substrate; and (d) forming at least one doped layer on a surface of the substrate. In one embodiment, the method also includes filtering the aerosol so as to remove aerosol particles outside of a particular range of sizes. Also described is a unique aerosol generator that is particularly useful in generating aerosols of rare-earth dopants. Particular embodiments directed to the fabrication of Yb-doped optical fibers are described.

Abstract: A large mode area optical fiber is configured to support multiple transverse modes of signal radiation within its core region. The fiber is a hybrid design that includes at least two axial segments having different characteristics. In a first axial segment the transverse refractive index profile inside the core is not radially uniform being characterized by a radial dip in refractive index. The first segment supports more than one transverse mode. In a second axial segment the transverse refractive index profile inside the core is more uniform than that of the first segment. The two segments are adiabatically coupled to one another. Illustratively, the second segment is a terminal portion of the fiber which facilitates coupling to other components. In one embodiment, in the first segment M12>1.0, and in the second segment M22<<M12. In a preferred embodiment, M12>>1.0 and M22˜1.0. In another embodiment, the optical fiber is coupled to a fiber stub.

Abstract: A large mode area optical fiber is configured to support multiple transverse modes of signal radiation within its core region. The fiber is a hybrid design that includes at least two axial segments having different characteristics. In a first axial segment the transverse refractive index profile inside the core is not radially uniform being characterized by a radial dip in refractive index. The first segment supports more than one transverse mode. In a second axial segment the transverse refractive index profile inside the core is more uniform than that of the first segment. The two segments are adiabatically coupled to one another. Illustratively, the second segment is a terminal portion of the fiber which facilitates coupling to other components. In one embodiment, in the first segment M2>1.0, and in the second segment M22<<M12. In a preferred embodiment, M12>>1.0 and M22˜1.0. In another embodiment, the optical fiber is coupled to a fiber stub.

Abstract: A method of fabricating a glass body that includes a multiplicity of constituents, at least one of which is a dopant (e.g., a rare-earth element) having a low vapor pressure (LVP) precursor comprises the steps of: (a) generating an aerosol from the LVP precursor; (b) separately generating vapors of the other constituents; (c) convecting the aerosol and vapors to deposition system including a substrate; and (d) forming at least one doped layer on a surface of the substrate. In one embodiment, the method also includes filtering the aerosol so as to remove aerosol particles outside of a particular range of sizes. Also described is a unique aerosol generator that is particularly useful in generating aerosols of rare-earth dopants. Particular embodiments directed to the fabrication of Yb-doped optical fibers are described.

Abstract: A large mode area, gain-producing optical fiber is configured to support multiple transverse modes of signal radiation within its core region. The fiber is a hybrid design that includes at least two axial segments having different characteristics. In a first axial segment the transverse refractive index profile inside the core is not radially uniform being characterized by a radial dip in refractive index. The first segment supports more than one transverse mode. In a second axial segment the transverse refractive index profile inside the core is more uniform than that of the first segment. The two segments are adiabatically coupled to one another. Illustratively, the second segment is a terminal portion of the fiber which facilitates coupling to other components. In one embodiment, in the first segment M12>1.0, and in the second segment M22<<M12. In a preferred embodiment, M12>>1.0 and M22˜1.0.

Abstract: A tunable optical fiber device comprises a length of fiber having a core having a certain refractive index; a cladding peripherally surrounding the core with a refractive index less than the refractive index of the core; and at least one hollow region disposed within the cladding in proximity to the core or within the core itself. Fluid (typically liquid) controllably moved within the hollow region modifies the effective index of the fiber and thereby tunes its characteristics.

Abstract: The invention involves providing a microstructured fiber having a core region, a cladding region, and one or more axially oriented elements (e.g., capillary air holes) in the cladding region. A portion of the microstructured fiber is then treated, e.g., by heating and stretching the fiber, such that at least one feature of the fiber microstructure is modified along the propagation direction, e.g., the outer diameter of the fiber gets smaller, the axially oriented elements get smaller, or the axially oriented elements collapse. The treatment is selected to provide a resultant fiber length that exhibits particular properties, e.g., mode contraction leading to soliton generation, or mode expansion. Advantageously, the overall fiber length is designed to readily couple to a standard transmission fiber, i.e., the core sizes at the ends of the length are similar to a standard fiber, which allows efficient coupling of light into the microstructured fiber length.

Abstract: The invention involves providing a microstructured fiber having a core region, a cladding region, and one or more axially oriented elements (e.g., capillary air holes) in the cladding region. A portion of the microstructured fiber is then treated, e.g., by heating and stretching the fiber, such that at least one feature of the fiber microstructure is modified along the propagation direction, e.g., the outer diameter of the fiber gets smaller, the axially oriented elements get smaller, or the axially oriented elements collapse. The treatment is selected to provide a resultant fiber length that exhibits particular properties, e.g., mode contraction leading to soliton generation, or mode expansion. Advantageously, the overall fiber length is designed to readily couple to a standard transmission fiber, i.e., the core sizes at the ends of the length are similar to a standard fiber, which allows efficient coupling of light into the microstructured fiber length.

Abstract: Embodiments of the invention include a singlemode optical fiber having an antimony (Sb) doped core region, a suitable cladding region formed on the core region, and one or more gratings written in the optical fiber. Optical fibers manufactured according to embodiments of the invention provide faster growth of grating strength, higher thermal stability, and longer photosensitive wavelength compared to conventional Ge doped silica optical fibers. The optical fiber is fabricated for applications such as fiber grating applications where the index of the core is modulated by UV radiation. Also, the addition of Sb in the core region of the singlemode optical fiber provides higher temperature (e.g., greater than 100° C.) applications of fiber gratings and a reduced degradation of the band rejection efficiency. Also, the optical fibers are more conducive to direct and non-destructive grating writing over polymer jackets with a longer photosensitive wavelength in the UV range.

Abstract: A tunable optical fiber device comprises a length of fiber having a core having a certain refractive index; a cladding peripherally surrounding the core with a refractive index less than the refractive index of the core; and at least one hollow region disposed within the cladding in proximity to the core or within the core itself. Fluid (typically liquid) controllably moved within the hollow region modifies the effective index of the fiber and thereby tunes its characteristics.

Abstract: The reproducibility of preforms made by solution doping is significantly improved by adding an internal heat source, such as N2O, as a processing gas during the soot deposition process. The addition of the internal heat source gas results in forming a surface soot layer which exhibits a relatively uniform and consistent morphology. The improvement in the soot surface morphology results in improving the uniformity of the amount of solution dopant retained in the soot layer from preform to preform.

Abstract: Embodiments of the invention include an optical fiber device such as a modulator, variable attenuator or tunable filter including an optical fiber having a core region, a cladding layer around the core region, and a controllable active material disposed in, e.g., capillaries or rings formed the cladding layer. The active materials include, e.g., electro-optic material, magneto-optic material, photorefractive material, thermo-optic material and/or materials such as laser dyes that provide tunable gain or loss. The application of, e.g., temperature, light or an electric or magnetic field varies optical properties of the active material, which, in turn, varies or affects the propagation properties of optical signals in the device. The optical device includes a tapered region that causes the core mode to spread into the cladding region and, simultaneously, allows the active material to be relatively close to the propagated modes, thus allowing interaction between the active material and the propagating modes.

Abstract: Applicants have discovered an apparatus and method effective for use in rendering an optical fiber resistant to losses caused by high-radiation environments such as in outerspace. The apparatus comprises an optical fiber, a housing surrounding the optical fiber defining an enclosed space between the exterior surface of the fiber and the housing, and a concentration of deuterium or hydrogen gases disposed within the enclosed space.

Abstract: Embodiments of the invention include an optical fiber device such as a modulator, variable attenuator or tunable filter including an optical fiber having a core region, a cladding layer around the core region, and a controllable active material disposed in, e.g., capillaries or rings formed the cladding layer. The active materials include, e.g., electro-optic material, magneto-optic material, photorefractive material, thermo-optic material and/or materials such as laser dyes that provide tunable gain or loss. The application of, e.g., temperature, light or an electric or magnetic field varies optical properties of the active material, which, in turn, varies or affects the propagation properties of optical signals in the device. The optical device includes a tapered region that causes the core mode to spread into the cladding region and, simultaneously, allows the active material to be relatively close to the propagated modes, thus allowing interaction between the active material and the propagating modes.

Abstract: An optical waveguide comprising a silica structure and a number of radiation shielding dopant atoms. At least some of the radiation shielding dopant atoms are chemically bonded with at least some of the constituents of silica structure. As such, the radiation shielding dopants are fixed within the silica structure to shield the optical waveguide from at least one of alpha-, beta-, gamma-, x-, and neutron-radiation.

Abstract: The disclosed method of making microstructured optical fiber comprises providing a mold, with a multiplicity of elongate elements extending into the mold and being maintained in a predetermined spatial arrangement with respect to the mold. Silica-containing sol is introduced into the mold and is caused to or permitted to gel, such that a gel body results. After removing the elongate elements from the gel body and removing the gel body from the mold, the gel body is dried, sintered and purified, and the microstructured fiber is drawn from the sintered body.

Abstract: The invention involves providing a microstructured fiber having a core region, a cladding region, and one or more axially oriented elements (e.g., capillary air holes) in the cladding region. A portion of the microstructured fiber is then treated, e.g., by heating and stretching the fiber, such that at least one feature of the fiber microstructure is modified along the propagation direction, e.g., the outer diameter of the fiber gets smaller, the axially oriented elements get smaller, or the axially oriented elements collapse. The treatment is selected to provide a resultant fiber length that exhibits particular properties, e.g., mode contraction leading to soliton generation, or mode expansion. Advantageously, the overall fiber length is designed to readily couple to a standard transmission fiber, i.e., the core sizes at the ends of the length are similar to a standard fiber, which allows efficient coupling of light into the microstructured fiber length.

Abstract: A properly designed MOF can simultaneously exhibit large anomalous dispersion at visible and near infrared wavelengths and support numerous transverse spatial modes that are essentially decoupled from one another, even in the presence of significant perturbations. In a MOF that includes an inner cladding region comprising at least one thin layer of air holes surrounding a core region, the key is to achieve a relatively large wave vector mismatch between the lowest order modes by appropriate design of the size of the core region and of the effective refractive index difference between the core region and the inner cladding region. In accordance with one aspect of our invention, MOFs are designed to exhibit simultaneously relatively large anomalous dispersion and essentially decoupled transverse spatial modes by making the diameter of the core region less than about 6 &mgr;m and the difference in effective refractive index between the core and cladding regions greater than about 0.1 (10%).