PURPOSE: Fibers for optical communication in which the refractive index distribution in recpect of with the fiber cross section is almost constant near the center of the core and changes in the peripheral part in accordance with a circularly symmetric function, thus having low transmission loss and wide transmissiue band.
CONSTITUTION: The core part in a range from the center of the core (r=0) to a certain radius is formed with no change in composition of doping elements, Ge, Al, P, Ti and Ga and then the peripheral part is made by changing the element composition stepwise in accordance with a circularly symmetric function to form said optical fiber. Or the core part includes a certain content of P and B of which the latter lower the refractive index and the content of Ge is kept unchanged in the part near the center and then changed in accordance with a circularly symmetric function. The resulting optical fibers have a wide band of 600W1000MHZ in frequency characteristic and is free from pulse split in pulse characteristic.
YOKOTA HIROSHI
SUZUKI SHIYUUZOU
| JPS5028846A | 1975-03-24 |