Non-linear optical fiber, optical fiber coil, and wavelength converter

An optical fiber coil comprising a nonlinear optical fiber which is wound at a predetermined diameter and generates a nonlinear phenomenon with respect to input light having a predetermined wavelength,

• said nonlinear optical fiber having as characteristics with respect to said input light:
• a mode field diameter of 5 μm or less;
• a polarization mode dispersion of 1 ps/km½ or less or a fixed plane of polarization;
• a zero-dispersion wavelength of not less than 1.5 μm but not greater than 1.6 μm;
• a cutoff wavelength of not less than 1.4 μm but not greater than 1.7 μm at a length of 2 m;
• a transmission loss of 3 dB/km or less;
• and
• a nonlinear coefficient of 10/W/km or more.

A wavelength converter comprising:

• an excitation light source for outputting excitation light having a predetermined wavelength;
• a multiplexing section for multiplexing and outputting said excitation light and a signal light;
• a nonlinear optical fiber for receiving therein said excitation light and signal light outputted from said multiplexing section and generating a nonlinear phenomenon with respect to said excitation light, said nonlinear optical fiber having as characteristics with respect to said excitation light:
• a mode field diameter of 5 μm or less,
• a polarization mode dispersion of 1 ps/km½ or less or a fixed plane of polarization,
• a zero-dispersion wavelength of not less than 1.5 μm but not greater than 1.6 μm,
• a cutoff wavelength of not less than 1.4 μm but not greater than 1.7 μm at a length of 2 m,
• a transmission loss of 3 dB/km or less, and
• a nonlinear coefficient of 10/W/km or more;
• and
• a wavelength-selecting section for selecting a wavelength of light to be outputted and outputting converted light having thus selected wavelength, said converted light being generated by said nonlinear optical fiber.