Optical fibre and optical communication system using it

Abstract

The present invention resides in an optical fiber able to form an optical transmitting line for wavelength division multiplexing transmission in a wavelength band of 1.5 mum using a Raman amplifier, and an optical communication system using this optical fiber. The optical fiber has an effective core area from 40 mum<2 >to 60 mum<2 >in a set wavelength band of at least one portion of a wavelength band of 1.5 mum; a dispersion value from 4 to 10 ps / nm / km at a wavelength of 1.55 mum; a dispersion slope set to a positive value equal to or smaller than 0.04 ps / nm<2> / km in a wavelength band of 1.55 mum; and a zero dispersion wavelength equal to or smaller than 1.4 mum. Further, a cutoff wavelength is set to be equal to or smaller than 1.5 mum at a length of 2 m, and a bending loss is set to be equal to or smaller than 5 dB / m at a diameter of 20 mm in the wavelength band of 1.5 mum. In a refractive index profile of the optical fiber, for example, a relative refractive index difference Delta1 of a first glass layer as an innermost layer with respect to a reference layer, and a relative refractive index difference Delta3 of the refractive index of a third glass layer as a third layer from an inner side with respect to the reference layer are set to be positive. Further, a relative refractive index difference Delta2 of a second glass layer as a second layer from the inner side with respect to the reference layer is set to be negative.

Description

technical field [0001] The present invention relates to an optical fiber for optical transmission such as wavelength division multiplexing (WDM) transmission, etc., such as optical transmission in a long band such as 1.5 microns, and an optical transmission system using this optical fiber. Background technique [0002] With the development of the information society, the communication information capacity tends to increase dramatically. When such information increases, wavelength division multiplexing transmission (WDM transmission) and time division multiplexing transmission (TDM transmission) are attracting attention. This wavelength-division multiplexing transmission uses one optical fiber to transmit signals of multiple wavelengths, and is therefore an optical transmission method suitable for large-capacity and high-bit-rate transmission. Currently working on research and development of wavelength division multiplexing transmission technology. [0003] It is currently ...

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Problems solved by technology

[0013] However, according to the existing researched optical fiber for wavelength division multiplexing transmission, the wavelength dispersion at 1.55μm wavelength is about -4ps / nm / km to +6ps / nm / km, and its dispersion slope is 0.05ps / nm 2 A value of / km or more, therefore, the zero dispersion wavelength is a value of 1.4 μm or longer, so as to cause interference of excitation light with a wavelength of about 1.4 μm and four-wave mixing, etc.

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