An integrated 2 x 2 semiconductor optical amplifier gate matrix switch is characterized for use in an optical packet buffer. Error-free performance for all port configurations is demonstrated for 40 Gb/s with less than 1-dB power penalty and an input power dynamic range of greater than 15 dB. Switching times are measured for decreasing optical input power to show an upper limit of 1-ns rise time (20%-80%). The factors limiting the maximum number of recirculations are explored toward optimizing future designs. It is concluded that the amplifier gate matrix switch is suitable for optical packet buffering.