Noise measurements in a short, near-ballistic, n
+-n
--n
+GaAs diode are reported. The device had a linear characteristic below 100 mA. It showed

noise at low frequencies and a white noise close to the thermal noise of the device conductance

at high frequencies. The

noise is most likely mobility fluctuation noise; we evaluated Hooge\´s parameter α and found a value of 1.95 × 10
-6at room temperature and 0.959 × 10
-6at liquid nitrogen temperature. We also observed a

noise spectrum turning over into
0.5spectrum at 77 K.