Abstract: An optical-fiber light amplifier using rare-earth-doped optical fibers. The light amplifier combines first and second excitation light from first and second sources to form combined excitation light and divides the combined excitation light for inverted distribution to both two optical fibers. The light entered one optical fiber and that entered the other optical fiber are polarized so as to be perpendicular to each other so that fluctuation of output level is prevented without mutual interference. Alternatively the first excitation light and the second excitation light may have different wavelengths; also in this case, fluctuation of level is prevented without any interference.

Abstract: An optical-fiber light amplifier using rare-earth-doped optical fibers. The light amplifier combines first and second excitation light from first and second sources to form combined excitation light and divides the combined excitation light for inverted distribution to both two optical fibers. The light entered one optical fiber and that entered the other optical fiber are polarized so as to be perpendicular to each other so that fluctuation of output level is prevented without mutual interference. Alternatively the first excitation light and the second excitation light may have different wavelengths; also in this case, fluctuation of level is prevented without any interference.

Abstract: A device for withdrawing liquid from a paper container having the upper wall provided with a fin-shaped projection, comprising a groove portion adapted to be engaged with the fin-shaped projection of the paper container and at least one hollow body formed on one side of the groove portion, said hollow body having a sharp edge portion which is inserted through the paper wall into the container and an open head for withdrawing the liquid housed in the paper container.