Abstract: The radio-over-fiber (RoF) transponder includes a converter unit adapted to convert RF electrical signals into optical signals and vice versa, and an antenna system electrically coupled to the converter unit. The antenna system includes first and second Z-shaped patch antenna elements formed on an antenna substrate. These patches are adapted to respectively transmit and receive radio-frequency (RF) electromagnetic radiation at a first frequency fA (e.g., 2.4 GHz) over a first picocell. The antenna system also includes a square patch antenna element formed atop the antenna substrate surface between the first and second Z-shaped patch antenna elements. The square patch antenna is adapted to transmit and receive RF electromagnetic radiation at a second frequency fB (e.g., 5.2 GHz) over a second picocell substantially co-located with the first picocell. One or more spaced-apart transponders can be supported by one or more optical fibers to form an array of picocells.

Abstract: A method for generating a linear single-polarization output beam comprises providing an optically active linearly birefringent and linearly dichroic fiber for propagating light and having a single polarization wavelength range and a gain bandwidth; optically pumping the optically active linearly birefringent and linearly dichroic fiber for obtaining fluorescence within the gain bandwidth; and aligning the single-polarization wavelength range to overlap a desired spectral region of the gain profile.

Abstract: The present invention relates to fiber bundles and methods for making fiber bundles. According to one embodiment of the invention, at the endface of the fused fiber bundle, the ratio of the cross-sectional area of the endface to the cross sectional area of the plurality of optical fibers is at least about 2.5. According to another embodiment of the invention, a fused fiber bundle includes a plurality of optical fibers, and a glass tube surrounding the terminal segments of the optical fibers, wherein the refractive index of the glass tube is less than the refractive index of the claddings of the optical fibers. Other embodiments of the present invention provide methods for making fused bundles.

Abstract: A method for generating a linear single-polarization output beam comprises providing an optically active linearly birefringent and linearly dichroic fiber for propagating light and having a single polarization wavelength range and a gain bandwidth; optically pumping the optically active linearly birefringent and linearly dichroic fiber for obtaining fluorescence within the gain bandwidth; and aligning the single-polarization wavelength range to overlap a desired spectral region of the gain profile.

Abstract: The radio-over-fiber (RoF) transponder includes a converter unit adapted to convert RF electrical signals into optical signals and vice versa, and an antenna system electrically coupled to the converter unit. The antenna system includes first and second Z-shaped patch antenna elements formed on an antenna substrate. These patches are adapted to respectively transmit and receive radio-frequency (RF) electromagnetic radiation at a first frequency fA (e.g., 2.4 GHz) over a first picocell. The antenna system also includes a square patch antenna element formed atop the antenna substrate surface between the first and second Z-shaped patch antenna elements. The square patch antenna is adapted to transmit and receive RF electromagnetic radiation at a second frequency fB (e.g., 5.2 GHz) over a second picocell substantially co-located with the first picocell. One or more spaced-apart transponders can be supported by one or more optical fibers to form an array of picocells.

Abstract: According to one example of the invention an optical fiber comprises: (i) silica based, rare earth doped core having a first index of refraction n1; (ii) at least one silica based cladding surrounding the core and having a second index of refraction n2, such that n1>n2; wherein at least one of the core or cladding is doped with Al2O3, such that the ratio of max wt % to min wt % of Al2O3 concentration is less than 2:1.

Abstract: An optical fiber including: (i) a silica based, rare earth doped core having a first index of refraction n1; (ii) a silica based inner cladding surrounding the core and having a second index of refraction n2, such that n1>n2, said inner cladding having a plurality of air holes extending longitudinally through the length of said optical fiber; (iii) a silica based outer cladding surrounding said inner cladding and having a third index of refraction n3, such that n2>n3, wherein said optical fiber supports a single polarization mode within the operating wavelength range.

Abstract: An optical fiber including: (i) a silica based, rare earth doped core having a first index of refraction n1; and (ii) at least one silica based cladding surrounding the core and having a second index of refraction n2, such that n1>n2, said cladding having a plurality of stress rods and a plurality of air holes extending longitudinally through the length of said optical fiber; wherein said optical fiber supports a single polarization mode or poses-polarization maintaining properties within the operating wavelength range.

Abstract: An optical fiber, comprising: a core with a first refractive index (n1); a silica based outer cladding surrounding the core, the outer cladding having a refractive index (n), such that the core is substantially surrounded by a gap situated between the core and the outer cladding, the gap containing at least one support structure adjacent to the outer cladding and situated between the outer cladding and the core, wherein the support structure is either hollow or gas filed and is not connected to any other support structure situated within the gap.

Abstract: A high power laser system comprising: a master laser; and a primary slave laser oscillator including a cavity comprising a rare earth doped fiber, said primary slave laser oscillator being actively injection-locked to said master laser, wherein said cavity provides an output exceeding 1 W of optical power.

Abstract: According to the present invention the optical fiber includes a core with a first refractive index (n1) and the innermost core region with the refractive index n0, a cladding surrounding the core, the cladding having a third refractive index (n3), wherein n1>n3 and n0<n1. According to some of the embodiments the optical fiber may also include a moat surrounding and abutting the core and situated between the core and the cladding, the moat having a second refractive index (n2), wherein n3>n2. It is preferable that at least one of the core, innermost core region and/or moat has a non-circular shape.

Abstract: An optical fiber comprising: (i) a silica based, rare earth doped core having a first index of refraction n1; (ii) a silica based inner cladding surrounding the core having a second index of refraction n2, such that n1>n2; (iii) a silica based outer cladding surrounding the inner cladding having a third index of refraction n3 such that n2>n3, wherein inner cladding diameter is at least 125 ?m.

Abstract: An optically active linear single polarization device includes a linearly birefringent and linearly dichroic optical waveguide (30) for propagating light and having single polarization wavelength range (48). A plurality of active dopants are disposed in a portion (34) of the linearly birefringent and linearly dichroic optical waveguide (30) for providing operation of the waveguide in an operating wavelength range (650) for overlapping the single polarization wavelength range (48).

Abstract: An optical fiber including: (i) a silica based, rare earth doped core having a first index of refraction n1; (ii) a silica based inner cladding surrounding the core and having a second index of refraction n2, such that n1>n2, said inner cladding having a plurality of air holes extending longitudinally through the length of said optical fiber; (iii) a silica based outer cladding surrounding said inner cladding and having a third index of refraction n3, such that n2>n3, wherein said optical fiber supports a single polarization mode within the operating wavelength range.

Abstract: An optical fiber, comprising: (i) a rare earth doped silica based elongated core with a first refractive index (n1) with an aspect ratio of 1:5 to 1; (ii) a silica based moat abutting and at least substantially surrounding the core, the moat having a refractive index n2, wherein n2<n1; (iii) a silica based inner cladding surrounding the moat, the inner cladding having a third refractive index (n3), wherein n1>n3; and n3>n2; (iv) a silica based outer cladding surrounding said inner cladding, the outer cladding having a fourth refractive index (n4), such that n4<n3; the optical fiber exhibits single polarization at the operating wavelength band.

Abstract: The present invention relates to fiber bundles and methods for making fiber bundles. According to one embodiment of the invention, at the endface of the fused fiber bundle, the ratio of the cross-sectional area of the endface to the cross sectional area of the plurality of optical fibers is at least about 2.5. According to another embodiment of the invention, a fused fiber bundle includes a plurality of optical fibers, and a glass tube surrounding the terminal segments of the optical fibers, wherein the refractive index of the glass tube is less than the refractive index of the claddings of the optical fibers. Other embodiments of the present invention provide methods for making fused bundles.

Abstract: According to the present invention the optical fiber includes a core with a first refractive index (n1) and the innermost core region with the refractive index n0, a cladding surrounding the core, the cladding having a third refractive index (n3), wherein n1>n3 and n0<n1. According to some of the embodiments the optical fiber may also include a moat surrounding and abutting the core and situated between the core and the cladding, the moat having a second refractive index (n2), wherein n3>n2. It is preferable that at least one of the core, innermost core region and/or moat has a non-circular shape.

Abstract: An optically-active air-clad fiber (30) includes a core (34, 84) that facilitates doping with an ion optically excitable and having a three-level optical transition when pumped at a first end (28) of an optical cavity (46) by a multimode pump source (72) at a pump wavelength (64) for lasing at a signal wavelength (66) different than the pump wavelength (64) at a second end (29) of the optical cavity (46), the core (34, 84) having a refractive index, wherein the core (34, 84) is transformed from the first end to proximate the second end (29) thereof such that the optically-active fiber (30) is multimode at the pump wavelength proximate to the first end (28), and is single-mode at the signal wavelength proximate to the second end (29). An air-clad (36, 86) surrounds at least one portion of the core (34, 84) and has a lower effective refractive index than the refractive index of the core (34, 84).

Abstract: According to one example of the invention an optical fiber comprises: (i) silica based, rare earth doped core having a first index of refraction n1; (ii) at least one silica based cladding surrounding the core and having a second index of refraction n2, such that n1>n2; wherein at least one of the core or cladding is doped with Al2O3, such that the ratio of max wt % to min wt % of Al2O3 concentration is less than 2:1

Abstract: According to one example of the invention an optical fiber comprises: (i) silica based, rare earth doped core having a first index of refraction n1; (ii) at least one silica based cladding surrounding the core and having a second index of refraction n2, such that n1>n2; wherein at least one of the core or cladding is doped with Al2O3, such that the ratio of max wt % to min wt % of Al2O3 concentration is less than 2:1.