Experimental measurements of gamma-radiation effects on fiber-optic cables

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.