In this study, we investigate the high-temperature characteristics and the temperature tuning of long-wavelength vertical-cavity semiconductor optical amplifiers (VCSOA) The temperature shift of the peak-signal gain is shown to depend on the mirror reflectivity of the VCSOA., Experimental results of temperature tuning of a 1.3-mum VCSOA are presented. We demonstrate 10 dB of fiber-to-fiber gain over a tuning range of approximately 8 run.