Abstract: After a wide-band DCF is wound around a bobbin to form an optical fiber coil 32, the latter is removed from the bobbin and placed into a bundle state (the state where the increase in transmission loss in the wavelength band of 1.55 ?m caused by distortions in winding is reduced by 0.1 dB/km or more) released from distortions in winding. A resin 42 is used as a coil-tidying member so as to secure the optical fiber coil 32 to a storage case 40 at four positions. Both ends of the optical fiber coil 32 are connected to pigtail fibers at fusion-splicing parts 44, respectively. Even when the storage case 40 is closed with a lid after the optical fiber coil 32 is secured to the storage case 40 with the resin 42, there remain interstices within the bundle of the optical fiber coil 32 and a space between the optical fiber coil 32 and the storage case 40. As a result, even when the optical fiber coil 32 in a bundle state is accommodated in the storage case 40, transmission loss and the like would not increase.

Abstract: After a wide-band DCF is wound around a bobbin to form an optical fiber coil 32, the latter is removed from the bobbin and placed into a bundle state (the state where the increase in transmission loss in the wavelength band of 1.55 &mgr;m caused by distortions in winding is reduced by 0.1 dB/km or more) released from distortions in winding. A resin 42 is used as a coil-tidying member so as to secure the optical fiber coil 32 to a storage case 40 at four positions. Both ends of the optical fiber coil 32 are connected to pigtail fibers at fusion-splicing parts 44, respectively. Even when the storage case 40 is closed with a lid after the optical fiber coil 32 is secured to the storage case 40 with the resin 42, there remain interstices within the bundle of the optical fiber coil 32 and a space between the optical fiber coil 32 and the storage case 40. As a result, even when the optical fiber coil 32 in a bundle state is accommodated in the storage case 40, transmission loss and the like would not increase.

Abstract: After a wide-band DCF is wound around a bobbin to form an optical fiber coil 32, the latter is removed from the bobbin and placed into a bundle state (the state where the increase in transmission loss in the wavelength band of 1.55 &mgr;m caused by distortions in winding is reduced by 0.1 dB/km or more) released from distortions in winding. A resin 42 is used as a coil-tidying member so as to secure the optical fiber coil 32 to a storage case 40 at four positions. Both ends of the optical fiber coil 32 are connected to pigtail fibers at fusion-splicing parts 44, respectively. Even when the storage case 40 is closed with a lid after the optical fiber coil 32 is secured to the storage case 40 with the resin 42, there remain interstices within the bundle of the optical fiber coil 32 and a space between the optical fiber coil 32 and the storage case 40. As a result, even when the optical fiber coil 32 in a bundle state is accommodated in the storage case 40, transmission loss and the like would not increase.

Abstract: There is disclosed a dispersion compensator for compensating for a chromatic dispersion and dispersion slope of an optical fiber transmission line, the dispersion compensator comprising a plurality of dispersion-compensating optical fibers connected to each other, the dispersion-compensating optical fibers each having a dispersion slope compensation ratio of at least 60% with respect to the optical fiber transmission line at a predetermined wavelength, one of said plurality of dispersion-compensating optical fibers having a dispersion slope compensation ratio of at least 80%, another of said plurality of dispersion-compensating optical fibers having a dispersion slope compensation ratio within the range of 60% to 100%.

Abstract: An optical fiber coil of the present invention includes an optical fiber, a storing case which stores the coiled optical fiber therein, and a filler in the storing case. The filler directly comes into contact with the glass portion of the optical fiber or contact with a thin film coating of not more than 1 &mgr;m being formed on a surface of the glass portion and having a hydrogen intrusion suppressing function. According to the optical fiber coil of the present invention, since the filler directly comes into contact with the glass portion of the optical fiber, the microbend loss can be further suppressed and the transmission can be stable.

Abstract: An optical fiber (1) which does not readily suffer influences of side pressures and can realize superior transmission characteristics, having a glass part (2, 3) having a core (2) and at least one cladding (3) and at least one covering layer (4a, 4b) formed around the glass part (2, 3), characterized in that the Young's modulus at 23° C. of the covering layer (4) without the glass part (2, 3) is not greater than 400 MPa. The Young's modulus measurement of the covering layer (4) is obtained by removing the glass part (2, 3) from the optical fiber (1) and putting the covering layer (4) to a tensile test.

Abstract: There is disclosed a dispersion compensator for compensating for a chromatic dispersion and dispersion slope of an optical fiber transmission line, the dispersion compensator comprising a plurality of dispersion-compensating optical fibers connected to each other, the dispersion-compensating optical fibers each having a dispersion slope compensation ratio of at least 60% with respect to the optical fiber transmission line at a predetermined wavelength, one of said plurality of dispersion-compensating optical fibers having a dispersion slope compensation ratio of at least 80%, another of said plurality of dispersion-compensating optical fibers having a dispersion slope compensation ratio within the range of 60% to 100%.

Abstract: An optical fiber coil of the present invention includes an optical fiber, a storing case which stores the coiled optical fiber therein, and a filler in the storing case. The filler directly comes into contact with the glass portion of the optical fiber or contact with a thin film coating of not more than 1 &mgr;m being formed on a surface of the glass portion and having a hydrogen intrusion suppressing function. According to the optical fiber coil of the present invention, since the filler directly comes into contact with the glass portion of the optical fiber, the microbend loss can be further suppressed and the transmission can be stable.