| 摘要 |
An optical waveguide for a communication system includes a graded index core formed from at least three glass-forming compounds with a profile having at least two alpha -type index profile terms. The core has a refractive index which is nc at the center of the core and which varies as a function of the radial distance r from the center of the core subststantially as: <IMAGE> where alpha iis defined by: <IMAGE> where N>/=2, DELTA =(nc2-n02)/2nc2, no is the refractive index of said compounds at r=a, Nc=nc- lambda dnc/d lambda where lambda is the wavelength of the light source, and the quantities DELTA i are parameters which can be varied provided the condition <IMAGE> is satisfied. |
