12 results about "Relative refractive index" patented technology

A multicore optical fiber may include a common cladding comprising a radius R4 defining a glass portion of the optical fiber and having a cladding relative refractive index Δ4. At least two waveguides may extend through the common cladding. Each waveguide may include a core region, an inner cladding region, and a depressed cladding region. Each core region may include a maximum relative refractive index Δ1max. Each inner cladding region may include a relative refractive index Δ2. Each depressed cladding region may include a minimum relative refractive index Δ3min and a trench volume from 20-45%µm2 such that Δ1max>Δ2>Δ3min, and Δ4>Δ3min. A cable cutoff wavelength of each waveguide is ≤1150 nm. The co-propagating and counter-propagating inter-waveguide cross talk between each waveguide and a nearest waveguide is <-35 dB at 1310 nm and <-20 dB at 1550 nm for application lengths of 20 m. A mode field diameter of each waveguide is 8.2-9.0 µm at 1310 nm.

A polarization maintaining optical fiber (1) has: a core (11); an inner layer (12) that surrounds the core (11) without a gap; a pair of stress applying portions (13) disposed at positions sandwiching the core (11); and a cladding (14) that encloses the inner layer (12) and the pair of stress applying portions (13), a mode field diameter of light of a wavelength of 1.55 μm is 9.3 μm or less in a case where the light propagates in the core (11), a cutoff wavelength is 1.32 μm or more in a case where the optical fiber length is 0.25 m and the stress applying portions (13) are wound one turn around an axis having a radius of 2 mm in a manner that a slow axis of the stress applying portions (13) is perpendicular to a surface of the axis, and a product of an area of a cross section of the inner layer (12) perpendicular to a length direction and an average of relative refractive index differences of the inner layer (12) as a whole with respect to the cladding (14) is -36% μm 2 or more and 0% μm 2 or less.

The object of this invention is to obtain, at a lower cost, an optical glass with a low temperature coefficient of relative refractive index that helps correct the effects of temperature changes on imaging characteristics, and preforms and optical elements using this optical glass. The optical glass, by mass%, contains 1.0% to 27.0% SiO2, 5.0% to 34.0% Ln2O3 (where Ln is one or more selected from the group consisting of La, Gd, Y, and Yb), more than 30.0% to 65.0% BaO, and 25.0% or less B2O3. The temperature coefficient of its relative refractive index (589.29 nm) (40–60 °C) is in the range of +3.0 × 10⁻⁶ to -10.0 × 10⁻⁶ (°C⁻¹).

This optical fiber comprises a core, an inner cladding, a trench, and an outer cladding. When the relative refractive index difference of the core is ∆1, the relative refractive index difference of the inner cladding is ∆2, the relative refractive index difference of the trench is ∆3, the relative refractive index difference of the outer cladding is ∆4, the outer diameter of the core is 2r1, the outer diameter of the inner cladding is 2r2, the outer diameter of the trench is 2r3, and the outer diameter of the outer cladding is 2r4, the following relationships are established.　2.2 ≤ r2 / r1 ≤ 3.6; 3μm ≤ r3 － r2 ≤ 12μm; 0.25% ≤ ∆1 － ∆2 ≤ 0.50%; − 0.70% ≤ ∆3 ≤ − 0.10%; A zero-dispersion wavelength is 1296-1306 nm. A zero-dispersion slope is 0.088 ps / nm2 / km or less. A 500-meter cable cutoff wavelength is 1260 nm or less. A bending loss for light with a wavelength of 1310 nm when the optical fiber is wound around a mandrel having a diameter of 15 mm is 0.5 dB or less per turn.

To provide an optical fiber that is suitable for reducing transmission loss and is highly manufacturable. [Solution] The optical fiber comprises a core made of silica glass and a cladding portion made of silica glass, surrounding the outer circumference of the core and having a refractive index lower than the maximum refractive index of the core. The core has a center core which has the highest average refractive index within the optical fiber, and the center core does not contain germanium as a dopant to increase the refractive index of the silica glass, and the relative refractive index difference Δclad between the refractive index of the cladding portion and the refractive index of the pure silica glass is 0% or more.

The multi-core optical fiber includes a plurality of cores, a first cladding, and a second cladding. The second cladding has a refractive index lower than a refractive index of each of the cores and higher than a refractive index of the first cladding. The multi-core optical fiber has a transmission loss of 0.22 dB / km or less. When an effective area of each of the cores is denoted as Aeff, a center-to-center distance between two cores is denoted as Λ, and a relative refractive index difference of each of the cores with respect to the refractive index of the first cladding is denoted as Δcore, Aeff1 is defined byAeff⁢1=18.6-4.63 ln⁢ (Δcore)+1.24Λ+2⁢4.1[ln⁢ (Δcore)]⁢2-6.05×10-3⁢Λ2-0.858Λ⁢ ln⁢ (Δcore),andthe multi-core optical fiber satisfies Condition below by using Aeff1.0.35≤Δcore≤1.25≤Λ≤5⁢00.8Aeff⁢1≤Aeff≤1.35Aeff⁢1

The cladding (12) includes an inner cladding (121) covering the outer periphery of the core (11), a trench (122) covering the outer periphery of the inner cladding, and an outer cladding (123) covering the outer periphery of the trench. The inner cladding has a lower refractive index than the core. The trench has a lower refractive index than the inner cladding. The outer cladding has a higher refractive index than the trench and a lower refractive index than the core. When the relative refractive index difference of the core with respect to the refractive index of pure silica is set as Δ1, the relative refractive index difference of the inner cladding with respect to the refractive index of pure silica is set as Δ2, the relative refractive index difference of the trench with respect to the refractive index of pure silica is set as Δ3, the radius of the outer periphery of the core is set as r1, the radius of the outer periphery of the inner cladding is set as r2, and the radius of the outer periphery of the trench is set as r3, r2 / r1 is 2.2 or more and 3.6 or less, r3-r2 is 3 μm or more and 10 μm or less, Δ1-Δ2 is 0.15% or more and 0.40% or less, and Δ3 is -0.70% or more and -0.10% or less.

This invention relates to a large effective area ultra-low attenuation multi-core optical fiber and its applications. The large effective area ultra-low attenuation multi-core optical fiber includes at least four core layers and a common cladding surrounding and covering the core layers. The core layers are symmetrically and uniformly distributed across the fiber cross-section. Each core layer is surrounded by an inner cladding and a recessed inner cladding layer, arranged sequentially from the inside to the outside. The common cladding layer includes a first outer cladding layer and a second outer cladding layer. The relative refractive index difference between the first and second outer cladding layers increases from the inside to the outside. This invention, through a multi-layer cladding structure of "inner cladding-recessed inner cladding-first outer cladding-second outer cladding layer," combined with the increasing relative refractive index difference between the first and second outer cladding layers from the inside to the outside, achieves a synergistic improvement in ultra-low attenuation, large effective area, ultra-low inter-core crosstalk, excellent bending resistance, and good system compatibility, providing an ideal transmission medium for long-distance, high-capacity space-division multiplexing optical communication systems.

The application relates to a high-uniformity fluorine-doped quartz piece, a preparation method and an optical fiber preform, which comprises the following steps: obtaining silica powder and fluoride powder with required mass based on the design relative refractive index difference of the fluorine-doped quartz piece, the mass of the fluorine-doped quartz piece, and a first mapping relationship of the relative refractive index difference of the fluorine-doped quartz piece with respect to the mass of the silica powder and the mass of the fluoride powder; uniformly mixing the silica powder and the fluoride powder to obtain a precursor powder; and heating and melting the precursor powder to make hydrogen fluoride generated by decomposition of the fluoride powder react with the silica powder, so that a high-uniformity fluorine-doped quartz piece is obtained. The application can solve the problems of poor uniformity of fluorine doping and low raw material utilization in the prior art.

A multicore optical fiber may include a common cladding comprising a radius R4 defining a glass portion of the optical fiber and having a cladding relative refractive index Δ4. At least two waveguides may extend through the common cladding. Each waveguide may include a core region, an inner cladding region, and a depressed cladding region. Each core region may include a maximum relative refractive index Δ1max. Each inner cladding region may include a relative refractive index Δ2. Each depressed cladding region may include a minimum relative refractive index Δ3min and a trench volume from 20-45% μm2 such that Δ1max>Δ2>Δ3min, and Δ4>Δ3min. A cable cutoff wavelength of each waveguide is ≤1150 nm. The co-propagating and counter-propagating inter-waveguide cross talk between each waveguide and a nearest waveguide is <−35 dB at 1310 nm and <−20 dB at 1550 nm for application lengths of 20 m. A mode field diameter of each waveguide is 8.2-9.0 μm at 1310 nm.

This optical fiber comprises: a glass fiber having a core, an inner cladding surrounding the core, and an outer cladding surrounding the inner cladding; and a covering resin layer covering the outer periphery of the glass fiber. The core contains germanium. When the diameter of the core is 2r1 and the diameter of the inner cladding is 2r2, 3 ≤ r2 / r1 ≤ 6 holds. The diameter of the core is 4.6-8.9 μm inclusive. When the relative refractive index difference of the core is ∆1, the relative refractive index difference of the inner cladding is ∆2, and the relative refractive index difference of the outer cladding is ∆3, 0.40% ≤ ∆1−∆2 ≤ 0.80% and −0.10% ≤ ∆2−∆3 ≤ 0.10% hold. Residual stress in the core is compressive stress. The mode field diameter at a wavelength of 1310 nm is 8.4 μm or less. The cable cutoff wavelength is less than 1530 nm. The diameter of the covering resin layer is 180 μm or less.