Fujikura Limited

Keisuke Uchiyama

Koichi Harada

Masahiro Horikoshi

Shoichiro Matsuo

Kuniharu Himeno

Shoji Tanigawa

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.

Optical fiber, transmission system, and wavelength division multiplexing system

A multi-tube burner is provided which includes a cylindrical outermost nozzle and at least one cylindrical inner nozzle provided coaxially with the outermost nozzle to form annular jet openings for gases used to manufacture a glass preform. The angle between a center axis of an outer circumference of the outermost nozzle and a distal end portion of each of the inner nozzles is 90&#xb0;&#xb1; not more than 3&#xb0;. Furthermore, the distance between the center axis of the outer circumference of the outermost nozzle and each of center axes of inner circumferences and outer circumferences of the inner nozzles is not more than 0.20 mm.

Multi-tube burner and glass preform manufacturing method using the same

An optical fiber and an optical fiber preform having optical characteristics, such as the wavelength dispersion, close to design values by controlling the amount of change in the refractive index in the core, thereby realizing high-quality and high-speed transmission, and manufacturing methods therefor. The optical fiber or the optical fiber preform is manufactured in a manner such that at each position in the area in which the relative refractive index of the core with respect to the cladding is 80% or higher of the maximum value of the relative refractive index, the absolute value of the rate of change of the relative refractive index with respect to the position along the diameter of the cladding is 0.5 or less, where the position along the diameter of the cladding is defined by percentage with respect to the diameter.

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Sakura, Japan

Keisuke Uchiyama