Ing. Marek Zikmund

This paper reports on our study of the effect of gamma-ray irradiation on two types of experimental fiber-optic cables. The first type of cable, CTFS, had a jelly-filling compound, whereas the second type, CTDS, was without the jelly. The cables contained three multi-mode (A, B, C) and five single-mode (D, E, F, G, H) optical fibers. The study was performed using two gamma-irradiation facilities with 60Co sources for slow long-term irradiation with the dose of 80.5 kGy at the low dose rate of 5.5 Gy/h and with the dose of 65.5 kGy at the higher dose irradiation rate of 0.94 kGy/h. After the irradiation with the dose of 80.5 kGy, the C fiber in the CTDS cable had the optical loss of 5.91 dB; 140 days after the gamma treatment at the wavelength of 1300 nm, it was 4.96 dB. The lowest optical losses for a single-mode fiber after irradiation with the dose of 65.5 kGy were found for the D fiber in the cable CTFS, namely 3.26 dB at 1490 nm and 3.49 dB at 1310 nm. In the fiber E in the CTDS cable, the optical loss was 3.62 dB at 1550 nm. In the fiber F in the CTDS cable, it was 3.86 dB at 1310 nm.

This paper reports on the optical properties of the erbium-doped fiber amplifier. I have studied transmission spectra of Erbium doped fibers and compare differences in gain of the amplifier between all optical pumping methods at wavelengths of 980 nm and 1480 nm for 3, 10 m, and 50 m long Erbium doped fibers. Results show, that the maximal reached gain was 26.1 dB with pumping on combination of wavelengths of 980 nm and 1480 nm from both sides with 19 dBm pumping power to 50 m long fiber amplifier.