Experimental measurements of the spectral absorption coefficient of infrared optical fibers. (March 2021) - Moore, Travis J.
Highlights: Measurement method of the spectral absorption coefficient of infrared optical fibers. Treatment of mathematical model of radiative transfer in optical fibers. Spectral absorption coefficient of arsenic trisulfide, ZBLAN, and indium fluoride optical fibers. Abstract: Infrared optical fibers are used in numerous applications in various industries. Knowledge of the radiative properties of optical fiber materials is important for the design and analysis of the processes in which the fibers are used. An experimental method for measuring the spectral absorption coefficient of infrared optical fibers using FTIR spectroscopy is presented. Blackbody radiation from a calibration source at different temperatures is transmitted through an optical fiber into an FTIR spectrometer. A mathematical model of the radiative heat transfer in the fiber is used to develop a linear spectral instrument response function relating the radiative energy from the calibration source to the output signal of the detection system. The spectral absorption coefficient of an infrared optical fiber is estimated from the ratio of the slopes of the instrument response functions for fibers of differing length. The method is used to estimate the room-temperature spectral absorption coefficient of infrared optical fibers made of arsenic trisulfide chalcogenide glass, ZBLAN glass, and indium fluoride glass.