An absorption cell for the 1.315 ㎛ iodine laser wavelength has been developed using iodine atoms in the ground state. The iodine have been produced by the dissociation of the gaseous molecular iodine, $I_2$, in a heated cell in the temperature ranges 400℃-800℃. The dissociation vessel is a sealed quartz cell of 1.3cm in diameter and 12cm long. The quartz cell is contained in a cylindrical glass vessel which is evacuated to $10^{-3}$ torr for thermal isolation. The absorption is investigated for various temperatures of the cell and for various energy densities of the laser beam. Small signal absorption is independent of energy density. These results are in good agreement with absorption theory by using rate equation. The absorption is saturated at 20 mJ/㎠ energy density. For the absorption measurements the iodine laser which has been developed in this laboratory is used. The output characteristics of the iodine laser has been investigated for the temporal and the spatial behaviors. The pulse duration obtained by using a pyroelectric detector is 2.5 μsec and the spatial distribution is 2mm in diameter. The laser power shows a saturation as the pressure of $C_2H_5I$ gas in the resonator increases beyond approximately 40 torr.