OPTICAL FIBER

摘要

The optical fiber of this invention is an optical fiber, which can generate white light that is adequately broadened in wavelength and which can stabilize the polarized conditions. The optical fiber of this invention generates, by means of nonlinear phenomena, white light in the wavelength bands at both sides of a pumping optical pulse that is input. The optical fiber of this invention is formed by covering the surroundings of a core (1) with a first cladding (2) and covering the surroundings of the first cladding (2) with a second cladding (3). The ratio ( DELTA 2/ DELTA 1) of the respective specific refractive index differences DELTA 1 and DELTA 2 of the core (1) and first cladding (2) with respect to the second cladding (3) is set in the range, -0.4 to -0.85, the ratio of outer diameter of the core (1) to the outer diameter of the first cladding (2) is set in the range, 0.4 to 0.7, and the specific refractive index difference DELTA 1 is set in the range, 0.6 to 1.2%. The transmission loss of light in the vicinity of a wavelength of 1.4 mu m is made less than or equal to 10dB/km. Stress-applying parts (4), which apply stress to core (1), are provided inside second cladding (3) so as to sandwich core (1) from both sides to form a polarization-maintaining optical fiber and the shortest distance between the stress-applying parts (4) is made 2.3 times or more the mode field diameter for the wavelength of the pumping optical pulse. <IMAGE>