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.

The paper presents the study of the effect of gamma rays on three types of single- mode optical fibers. We measured changes in optical losses after irradiation and studied the relaxation process.

We report on the properties of the Power over Fiber (PoF) system using a High-Power Laser Source (HPLS) operating at 1470 nm with an optical power of up to 2.0 W. Graded-index and step-index optical fibers with a core diameter of 50 µm were used for transmission and two types of Photovoltaic Power Converters (PPCs) were used for optical power to electricity conversion. We experimentally demonstrated the powering to a distance of 5855 m, where we achieved the electric power of 44.4 mW and estimated the possibility of powering to distances longer than 9000 m with the input optical power of 15 W, where we expect to achieve the delivery of the electric power around 150 mW.

We report on the properties of the Power over Fiber (PoF) transmission link using a High-Power Laser Source operating at 976 nm and using three types of optical fiber with a core diameter of 50 mu m. Two step-index profile multimode optical fibers and one fiber with a gradient index were used for optical power transmission. Optical light was converted to electricity using commercially available Photovoltaic Power Convertors (PPCs) with a maximal optical input power of 1.5 W and experimental PPCs with a maximal optical input power of 4.0 W. We experimentally proved optical power transmission up to a distance of 300 m. In the case of the commercially available working PPC and using the gradient index fiber we achieved a result of 0.534 W of electrical power and using the experimental PPC we achieved 0.645 W. In the case of the step-index optical fiber, the result was 1.3 W.

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.