  We performed a transport measurement in a ballistic Aharonov-Bohm ring and a
Fabry-Perot type interferometer. In both cases we found that the interference
signal is reversed at a certain bias voltage and that the visibility decays
exponentially as a function of temperature, being in a strong analogy with
recent reports on the electronic Mach-Zehnder interferometers. By analyzing the
data including those in the previous works, the energy scales that characterize
the dephasing are found to be dominantly dependent on the interferometer size,
implying the presence of a universal behavior in ballistic interferometers in
both linear and non-linear transport regimes.
