Title:
【発明の名称】増幅用光ファイバ
Document Type and Number:
Japanese Patent JP2960674
Kind Code:
B2
Abstract:
PROBLEM TO BE SOLVED: To provide an optical fiber in which the diameter of a core is made large as far as possible, by which the amplification factor of signal light is increased and which obtains an optimum condition by a method in which the cutoff wavelength of the core is made smaller than the wavelength of the signal light and the relative index difference between the core and a first clad is set so as to become a specific value or higher. SOLUTION: A first clad and a second clad as two layers are formed on the outer circumference of a single-mode core, the core is doped with quaternary rare-earth elements, and the refractive index of the second clad is set to be smaller than that of the first clad. The cutoff frequency λc of the core (h) is set at a value which is smaller than the wavelength of signal light to be amplified and which is approximate to the wavelength of the signal light as fas as possible. The relative index difference between the core (h) and the first clad (i) is set at a value of 0.15% or higher and a value which is approximate to the value. Thereby, in a state that a single mode is maintained with reference to the wavelength of the signal light, the diameter of the core is made large as fas as possible, and an optimum condition to increase the absorption efficiency of excited light can be obtained.
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Inventors:
YOSHIDA MINORU
SUDO TAKAHIDE
OMAE TOSHIKAZU
SHIMOYAMA YOSHIO
SASAKI TOSHIHISA
MYAZAKI TETSUYA
KARASAWA YOSHIO
SUDO TAKAHIDE
OMAE TOSHIKAZU
SHIMOYAMA YOSHIO
SASAKI TOSHIHISA
MYAZAKI TETSUYA
KARASAWA YOSHIO
Application Number:
JP1182696A
Publication Date:
October 12, 1999
Filing Date:
January 26, 1996
Export Citation:
Assignee:
MITSUBISHI DENSEN KOGYO KK
EI TEI AARU KODENPA TSUSHIN KENKYUSHO KK
EI TEI AARU KODENPA TSUSHIN KENKYUSHO KK
International Classes:
G02B6/00; G02B6/02; G02B6/036; H01S3/06; H01S3/07; H01S3/10; H01S3/17; (IPC1-7): H01S3/06; G02B6/16; G02B6/22; H01S3/10
Domestic Patent References:
| JP3238883A | ||||
| JP4192481A | ||||
| JP77216A | ||||
| JP818129A | ||||
| JP537045A | ||||
| JP1207705A |
Other References:
【文献】米国特許5530709(US,A)
Attorney, Agent or Firm:
Kazuhide Okada