Abstract: An optical fiber has a first mode field diameter in a dominant mode of an acoustic mode generated in the optical fiber different from a second mode field diameter in a light intensity distribution of the optical fiber. Furthermore, a transmission system is configured to perform an analog signal transmission, a baseband transmission, or an optical SCM transmission by use of the optical fiber.

Abstract: A single-mode optical fiber has a prescribed mode field diameter (MFD1 (?m)) at a first wavelength ?1, in which a bending loss when measured at a second wavelength ?2 (?m) and wound with a bending radius r (mm) is Lb (dB) for one bending, a connector/splice loss with an optical fiber that has a prescribed mode field diameter MFD2 (?m) at the first wavelength ?1 is Ls (dB) for one connection/splice point at the second wavelength ?2 (?m), and an mode field diameter dependence of a total loss coefficient calculated by a formula (1) has a local minimal value in a range of MFD1±0.5 ?m, with the formula (1) being as follows: L=ws·Ls+wb·Lb,??(1) ws+wb=1,??(2) ws>0, wb>0,??(3) where ws and wb in the formula (1) represent dimensionless weighting factors and are set within a range that satisfies the formulas (2) and (3).

Abstract: A dispersion compensating optical fiber for NZ-DSFs, includes: an uncovered dispersion compensating optical fiber; a double-layered resin coating disposed around the uncovered dispersion compensating optical fiber; and an outer coating layer having a thickness of 3 to 7 ?m, containing silicone in an amount of 1 to 5% by weight, and disposed around the double-layered resin coating. The outer diameter of the uncovered dispersion compensating optical fiber is in a range from 90 to 125 ?m, an outer diameter of the dispersion compensating optical fiber is in a range from 180 to 250 ?m, and the amount of silicone contained in the outer coating layer is determined such that an adhesive property of the outer coating layer is 1 gf/mm or less.

Abstract: In a method of measurement of the birefringence of an optical fiber, the round-trip Jones matrix R(z) for a first interval (0, z) from a measurement starting point 0 in the optical fiber for measurement to a prescribed position z, and the round-trip Jones matrix R(z+?z) for a second interval (0, z+?z) from the measurement starting point 0 to a position z+?z differing from the position z, are acquired, the eigenvalues ?1, ?2 of the matrix R(z+?z)R(z)?1 are determined, and by computing the following equations (1) and (2), ? = arg ? ( ? 1 ? 2 ) 2 ( 1 ) ? ? ? n = ?? 2 ? ? · ? ? ? z ( 2 ) (where ? represents the phase difference between linear polarization components due to birefringence, ?n represents birefringence, and ? represents wavelength), the birefringence in the infinitesimal interval ?z from the position z to the position z+?z is obtained.

Abstract: 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 ?m to 7.9 ?m, 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.

Abstract: A photonic band gap fiber is provided having multiple air holes in a silica portion extending in the longitudinal direction of the fiber. The fiber includes a cladding containing an air hole periodic structure in an extended triangular lattice configuration, wherein first rows each having a number of air holes at a first pitch are arranged alternately in the cross section of the fiber with multiple second rows of air holes each with multiple air holes at a second pitch which is twice the first pitch. The fiber further includes an air hole core.

Abstract: A higher order mode dispersion compensating fiber includes an optical fiber and a first loss layer which is provided within the fiber and which attenuates a lower order mode propagating through the optical fiber while not attenuating a higher order mode which is higher than the lower order mode. A dispersion compensating fiber mode converter for a higher order fiber includes a single mode fiber; a higher order mode dispersion compensating fiber; and a fused and extended portion which has been formed by fusing and extending the single mode fiber and the higher order mode fiber. The fused and extended portion converts between the LP01 mode of the single mode fiber and the LP02 mode of the higher order mode dispersion compensating fiber.

Abstract: A graded-index multimode fiber includes a core made of silica glass, the core having a central region and an outer peripheral region, and a cladding which is provided at an outer periphery of the core. The central region contains one of germanium and phosphorus, and the outer peripheral region contains fluorine.

Abstract: An optical fiber that includes a core containing a first concentration of germanium, an inner cladding arranged on the core, the inner cladding containing a second concentration of germanium and having a first diffusion coefficient, and an outer cladding arranged on the inner cladding, the outer cladding having a second diffusion coefficient, where the first diffusion coefficient is larger than the second diffusion coefficient, and where the first concentration of germanium is about 200% or more of the second concentration of germanium. An optical fiber constructed in this manner can be spliced with an optical fiber having a different MFD, such as a single-mode optical fiber or an erbium-doped optical fiber, with low splice loss and a sufficient splicing strength.

Abstract: A photonic band gap fiber is provided having multiple air holes in a silica portion extending in the longitudinal direction of the fiber. The fiber includes a cladding containing an air hole periodic structure in an extended triangular lattice configuration, wherein first rows each having a number of air holes at a first pitch are arranged alternately in the cross section of the fiber with multiple second rows of air holes each with multiple air holes at a second pitch which is twice the first pitch. The fiber further includes an air hole core.

Abstract: A single-mode optical fiber has a prescribed mode field diameter (MFD1 (?m)) at a first wavelength ?1, in which a bending loss when measured at a second wavelength ?2 (?m) and wound with a bending radius r (mm) is Lb (dB) for one bending, a connector/splice loss with an optical fiber that has a prescribed mode field diameter MFD2 (?m) at the first wavelength ?1 is Ls (dB) for one connection/splice point at the second wavelength ?2 (?m), and an mode field diameter dependence of a total loss coefficient calculated by a formula (1) has a local minimal value in a range of MFD1±0.5 ?m, with the formula (1) being as follows: L=ws·Ls+wb·Lb,??(1) ws+wb=1,??(2) ws>0, wb>0,??(3) where ws and wb in the formula (1) represent dimensionless weighting factors and are set within a range that satisfies the formulas (2) and (3).

Abstract: A single-mode optical fiber has a prescribed mode field diameter (MFD1 (?m)) at a first wavelength ?1, in which a bending loss when measured at a second wavelength ?2 (?m) and wound with a bending radius r (mm) is Lb (dB) for one bending, a connector/splice loss with an optical fiber that has a prescribed mode field diameter MFD2 (?m) at the first wavelength ?1 is Ls (dB) for one connection/splice point at the second wavelength ?2 (?m), and an mode field diameter dependence of a total loss coefficient calculated by a formula (1) has a local minimal value in a range of MFD1±0.5 ?m, with the formula (1) being as follows: L=ws·Ls+wb·Lb,??(1) ws+wb=1,??(2) ws>0, wb>0??(3) where ws and wb in the formula (1) represent dimensionless weighting factors and are set within a range that satisfies the formulas (2) and (3).

Abstract: The invention relates to nanostructure and its manufacturing method. In the manufacturing method of a nanostructure, first anisotropic crystalline particles, connectors having end to be connected to a specific crystal face of each of said crystalline particles, and second particles to be connected to the other end of each of said connectors are prepared. First ends of the connectors are connected to specific crystal faces of the first crystalline particles, and simultaneously or before or after the connection, the second ends of the connectors are connected to the second particles. A nanostructure formed by this method has a three-dimensional structure which does not have a closest packing structure.

Abstract: An optical fiber that includes a core containing a first concentration of germanium, an inner cladding arranged on the core, the inner cladding containing a second concentration of germanium and having a first diffusion coefficient, and an outer cladding arranged on the inner cladding, the outer cladding having a second diffusion coefficient, where the first diffusion coefficient is larger than the second diffusion coefficient, and where the first concentration of germanium is about 200% or more of the second concentration of germanium. An optical fiber constructed in this manner can be spliced with an optical fiber having a different MFD, such as a single-mode optical fiber or an erbium-doped optical fiber, with low splice loss and a sufficient splicing strength.

Abstract: In a method of measurement of the birefringence of an optical fiber, the round-trip Jones matrix R(z) for a first interval (0, z) from a measurement starting point 0 in the optical fiber for measurement to a prescribed position z, and the round-trip Jones matrix R(z+?z) for a second interval (0, z+?z) from the measurement starting point 0 to a position z+?z differing from the position z, are acquired, the eigenvalues ?1, ?2 of the matrix R(z+?z)R(z)?1 are determined, and by computing the following equations (1) and (2), ? = arg ? ( ? 1 ? 2 ) 2 ( 1 ) ? ? ? ? n = ?? 2 ? ? · ? ? ? ? z ( 2 ) (where ? represents the phase difference between linear polarization components due to birefringence, ?n represents birefringence, and ? represents wavelength), the birefringence in the infinitesimal interval ?z from the position z to the position z+?z is obtained.

Abstract: An optical fiber that includes a core containing a first concentration of germanium, an inner cladding arranged on the core, the inner cladding containing a second concentration of germanium and having a first diffusion coefficient, and an outer cladding arranged on the inner cladding, the outer cladding having a second diffusion coefficient, where the first diffusion coefficient is larger than the second diffusion coefficient, and where the first concentration of germanium is about 200% or more of the second concentration of germanium. An optical fiber constructed in this manner can be spliced with an optical fiber having a different MFD, such as a single-mode optical fiber or an erbium-doped optical fiber, with low splice loss and a sufficient splicing strength.

Abstract: An optical fiber has a first mode field diameter in a dominant mode of an acoustic mode generated in the optical fiber different from a second mode field diameter in a light intensity distribution of the optical fiber. Furthermore, a transmission system is configured to perform an analog signal transmission, a baseband transmission, or an optical SCM transmission by use of the optical fiber.

Abstract: A method of measuring polarization mode dispersion (PMD) of an optical fiber, includes estimating PMD when an optical fiber is formed as an optical cable, from a beat length when the optical fiber is wound around a bobbin, and an average coupling length when the optical fiber is formed as the optical cable.

Abstract: A hole-assisted holey fiber is provided. The holey fiber includes a core region; a cladding region around the core region, and a plurality of holes in the cladding region around the core region. The core region has a higher refractive index than that of the cladding region. The holes form an inner hole layer and an outer hole layer, and the inner hole layer has the same number of holes as the number of the holes in the outer hole layer. The outer layer holes are provided in locations in which inner holes are absent when viewed from the center of the core region, and holes defining the same layer have the same diameter. A distance ?1 from a center of the core region to a center of an inner hole and a distance ?2 from the center of the core region to a center of an outer hole satisfy the relationship ?1<?2, and a diameter d1 of an inner hole and a diameter d2 of an outer hole satisfy the relationship d1?d2.

Abstract: A polarization-maintaining optical fiber which exhibits an excellent polarization-maintaining performance and significantly low splice loss when spliced with a polarization-maintaining optical fiber having a cladding 125 ?m in diameter even if the polarization-maintaining optical fiber has a small-diameter cladding of about 80 ?m. The polarization-maintaining optical fiber includes a core, a pair of stress-applying parts provided radially outwardly with respect to the core, and a cladding which surrounds the core and the stress-applying parts. With a diameter D of the stress-applying parts between 21 ?m and 32 ?m, a distance R between the stress-applying parts between 6 ?m and 17 ?m, and a relative refractive index difference ? between 0.3% to 0.5%, a sufficiently large mode field diameter (MFD) is obtained; thus splice loss can be reduced.