Denisov

pp. 35-44

pp. 319-333

In this article optical losses within the temperature range from 300 to 1500 K were investigated in visible and NIR spectral ranges for silica based optical fibers for the first time. It was shown that there is a significant increase in optical losses in the temperature range of 1050 - 1200 º C.  Optical losses reach their maximum at the temperature of 1200 º C at the wavelength of 400 nm; the maximum value for a silica-based optical fiber was approximately 5 dB/m, for a germanosilicate fiber ~ 4 dB / m, for a phosphosilicate fiber ~ 1.5 dB / m and for an aluminosilicate fiber ~ 45 dB / m. By the example of the aluminosilicate fiber it was shown that optical losses in the wavelength range of 380-850 nm could be associated with nano- and microcrystalline inclusions which are formed as a result of fiber annealing.

This work covers the study of basic characteristics and parameters of optical fiber Bragg gratings (FBG). The paper describes the main theoretical calculation methods of FBG spectral reflection and transmission coefficients and shows FBG reflection spectra measured in two different ways: by using a spectrum analyzer and a broadband pump source, and also by newly created units. The authors compared the theoretically calculated reflection spectra with the experimentally obtained by two different methods.