Effect of temperature on the absorption loss of chalcogenide glass fibers

The change in the absorption loss of IR-transmitting chalcogenide glass fib ers in the temperature range? of -90 degrees C less than or equal to T less than or equal to 70 degrees C was investigated. For sulfur-based glass fib ers the change in loss relative to room temperature was slightly affected b y the temperature in the wavelength region of 1-5 mu m. For lambda greater than or equal to 6 mu m the change in loss was mainly due to multiphonon ab sorption. The change in loss for tellurium-based glass fibers increased sig nificantly at T = 60 degrees C. The increase in the loss at short wavelengt hs (lambda less than or equal to 4.1 mu m) was due to electronic excitation s in the tail states. Between 5 and 9 mu m there was noticeable free-carrie r absorption. Beyond lambda greater than or equal to 9 mu m, multiphonon ab sorption dominated the loss spectrum. (C) 1999 Optical Society of America.