384 results about "Mode field diameter" patented technology

A multi-core fiber includes an even number of six or more of cores and a clad that surrounds the outer circumferential surfaces of the cores. The cores are formed of two types of cores and in which an effective refractive index difference in a fundamental mode is 0.002 or less in a predetermined range or more that the effective refractive index difference in the fundamental mode is varied according to a core pitch. Two types of the cores are alternately and annularly disposed at regular spacings. A difference in the mode field diameter of light propagating through the cores is 1 μm or less.

A single-mode optical fiber includes a central core, an intermediate cladding, a depressed trench, and an external optical cladding. The central core has a radius r₁ and a positive refractive index difference Δn₁ with the optical cladding. The intermediate cladding has a radius r₂ and a positive refractive index difference Δn₂ with the optical cladding, wherein Δn₂ is less than Δn₁. The depressed trench has a radius r₃ and a negative index difference Δn₃ with the optical cladding. At a wavelength of 1310 nanometers, the optical fiber has a mode field diameter (MFD) between 8.6 microns and 9.5 microns and, at a wavelength of 1550 nanometers, the optical fiber has bending losses less than about 0.25×10⁻³ dB/turn for a radius of curvature of 15 millimeters. At a wavelength of 1260 nanometers, attenuation of the LP11 mode to 19.3 dB is achieved over less than 90 meters of fiber.

The present invention relates in general to coupling of light from one or more input waveguides to an output waveguide or output section of a waveguide having other physical dimensions and/or optical properties than the input waveguide or waveguides. The invention relates to an optical component in the form of a photonic crystal fibre for coupling light from one component/system with a given numerical aperture to another component/system with another numerical aperture. The invention further relates to methods of producing the optical component, and articles comprising the optical component, and to the use of the optical component. The invention further relates to an optical component comprising a bundle of input fibres that are tapered and fused together to form an input coupler e.g. for coupling light from several light sources into a single waveguide. The invention still further relates to the control of the spatial extension of a guided mode (e.g. a mode-field diameter) of an optical beam in an optical fibre. The invention relates to a tapered longitudinally extending optical waveguide having a relatively larger cross section that over a certain longitudinal distance is tapered down to a relatively smaller cross section wherein the spatial extent of the guided mode is substantially constant or expanding from the relatively larger to the relatively smaller waveguide cross section. The invention may e.g. be useful in applications such as fibre lasers or amplifiers, where light must be coupled efficiently from pump sources to a double clad fibre.

An optical fiber suitable for use in a single fiber or multifiber optical connector or array is structured with a core region and a cladding region surrounding the core region, and exhibits a bending loss of a fundamental mode of the fiber at a wavelength λ is lower than 0.1 dB/m at a diameter of 15 mm, a mode-field diameter of the fundamental mode at an end of the fiber at the wavelength λ is between 8.0 μm and 50 λ, and a bending loss of a first higher-order mode at the wavelength λ is higher than 1 dB/m at a diameter of 30 mm. The fiber may be multistructured, wherein the cladding region comprises a main medium and a plurality of sub medium regions therein to form a spatially uniform average refractive index.

An optical coupler is formed of a low index material and exhibits a mode field diameter suitable to provide efficient coupling between a free space optical signal (of large mode field diameter) and a single mode high index waveguide formed on an optical substrate. One embodiment comprises an antiresonant reflecting optical waveguide (ARROW) structure in conjunction with an embedded (high index) nanotaper coupling waveguide. Another embodiment utilizes a low index waveguide structure disposed in an overlapped arrangement with a high index nanotaper coupling waveguide. The low index waveguide itself includes a tapered region that overlies the nanotaper coupling waveguide to facilitate the transfer of the optical energy from the low index waveguide into an associated single mode high index waveguide. Methods of forming these devices using CMOS processes are also disclosed.

A single-mode optical fiber has a cut-off wavelength of 1260 nm or less, a zero-dispersion wavelength in the range of 1300 nm to 1324 nm, a zero-dispersion slope of 0.093 ps/nm²/km or less, a mode field diameter at a wavelength of 1310 nm in the range of 5.5 μm to 7.9 μm, and a bending loss of 0.5 dB or less at a wavelength of 1550 nm, the bending loss being produced when the fiber is wound around a 10-mm radius for 10 turns.

The present invention embraces a single-mode optical fiber typically having reduced bending losses. The optical fiber includes a central core, an intermediate cladding, a buried trench, and an outer cladding. The optical fiber typically has (i), at a wavelength of 1310 nanometers, a mode field diameter with a nominal value of between about 8.6 microns and 9.5 microns (and a tolerance of ±0.4 micron), (ii) a cable cut-off wavelength of no more than 1260 nanometers, and (iii), for a bending radius of 15 millimeters at a wavelength of 1550 nanometers, bending losses of no more than 0.03 dB/turn.

An optical fiber, made of silica-based glass, comprising a core and a cladding. The optical fiber having a mode field diameter of 6.5 μm or larger at a wavelength of 1300 nm, transmitting light with a wavelength of 1250 nm in a single mode, and having a bending loss of 1 dB/turn or smaller at a wavelength of 1300 nm when the optical fiber is bent with a curvature radius of 1.5 mm.

Monolithic structures for coupling either a vertical-cavity surface emitting laser (VCSEL) or a half-cavity vertical cavity surface emitting laser into a single-mode optical fiber are provided. The monolithic structures include a coupler, which comprises a pellet comprising a piece of solid silica glass and a length of graded-index multimode fiber serving as a gradient index lens. Various coupler configurations are provided for handling the cases in which the diameter from the VCSEL is larger or smaller than the diameter of the single-mode fiber. In the case of the half-cavity VCSEL, the single-mode optical fiber including therein an embedded Bragg grating, the Bragg grating reflecting the seed light from the VCSEL, thus providing feedback for laser action. The fiber-coupled laser evidences increased mode field diameter and single-mode operation.

A fiber optic connector having a double-clad specialty optical stub fiber with a deep index core-to-inner-cladding profile and a raised index outer-cladding profile. The double-clad optical stub fiber abuts against a single-clad field optical fiber of the single-mode type to form an interface across which the primary mode traverses without significantly interfering with higher-order modes. The ratio of the radius of the inner cladding to the radius of the core of the stub fiber is less than 6.5:1. The index profile of the refractive index of the inner cladding is deep relative to the refractive index of the core to confine the primary mode within the core. The raised refractive index of the outer-cladding pulls the higher-order modes deeper into that region, reducing interference with the primary mode. The respective core diameters of the field and stub fibers are matched to avoid mode-field diameter mismatch.

A large-mode-area (LMA) optical fiber (10) that operates as a single-mode optical fiber. The optical fiber includes a core region (20) surrounded by an inner cladding (32), which in turn is surrounded by an outer cladding (40). The inner cladding includes at least one up-doped ring region (32R1). The ring region is configured to form a large attenuation differential between the higher-order modes and the fundamental mode so only that the fundamental mode remains traveling in the optical fiber. If necessary, the optical fiber can include a bend (10B) having a select “resonant” bend diameter (DB) that increases the relative attenuation of the fundamental and higher-order modes. The optical fiber supports an effective mode field diameter (MFD) of up to 40 μm to 50 μm. As a result, detrimental non-linear effects are suppressed, which allows the optical fiber to carry substantially more optical power than conventional LMA optical fibers. The LMA optical fiber is thus eminently suited for a number of optical-fiber-based applications calling for high optical power, such as fiber lasers and pump sources for wavelength conversion.

A compact, inexpensive and rugged fiber collimating lens and lens array achieve large beam diameters and provide long working distances. A special single-mode fiber is inserted between a standard single-mode input fiber and a GRIN fiber lens, typically quarter-pitch or slightly longer. The specialty fiber condenses the mode field diameter (MFD) of the beam in the input fiber into its smaller MFD. As a result, the fiber collimating lens provides greater beam expansion due to the larger divergence angle of the specialty fiber, which in turn provides longer working distances.

Optical fibers to form an optical transmission line suitable for WDM transmission in a wide-spreading wavelength band, having the following characteristics and parameters: a dispersion in absolute value of 0.5 ps/nm/km to 9 ps/nm/km in a wavelength band of 1430 nm to 1625 nm, a dispersion slope in absolute value of 0.04 ps/nm²/km or less at a wavelength of 1550 nm, a mode field diameter of 7 μm or less at a wavelength of 1550 nm and a cable cutoff wavelength of less than 1430 nm; core 11 surrounded by cladding 7, core 11 being at least two-layered (first layer 1 at the center and second layer 2 surrounding the first layer; relative refractive index of glass layer Δ1 with reference to the cladding being adjusted to not less than 0.6 but not more than 1.6%, relative refractive index of second layer Δ2 with reference to the cladding being adjusted to a negative value.

This invention relates to a bending-insensitive single module optics fiber and its process method. Its wave-guide structure comprises core layer and cover layer. Its process adopts PCVD work that the materials are burned solid without the oxygen and Freon with different proportions to get the fiber. The fiber bending consumption lies between 1310nm wavelength and 1550nm wavelength relative to regular 0.652 fibers and its fiber module field diameter is 7í‚0.8ª–m and its zero color diffusion wavelength is near 1310nm.

In an optical fiber ribbon 1 according to the present invention, four optical fibers 10, 20, 30 and 40 are arranged in parallel to each other in a plane, a part of the periphery of these four optical fibers is covered with a ribbon matrix 51, but no rest thereof is covered with the ribbon matrix. First areas covered with the ribbon matrix 51 and second areas uncovered with the ribbon matrix alternate with each other along the longitudinal direction thereof. Alternatively, the optical fiber ribbon 1 is covered with the ribbon matrix over its entire length. In the glass section of each optical fibers, the mode field diameter defined by the definition of Petermann-I at a wavelength of 1.55 μm is 8 μm or less, and the cable cutoff wavelength is 1.26 μm or less.