  We create a non-magnetic CMOS-compatible optical isolator on a silicon chip.
The isolator is based on indirect interband photonic transition, induced by
electrically-driven dynamic refractive index modulation. We demonstrate an
electrically-induced non-reciprocity: the transmission coefficients between two
single-mode waveguides become dependent on the propagation directions only in
the presence of the electrical drive. The contrast ratio between forward and
backward directions exceeds 30dB in simulations. We experimentally observe a
strong contrast (up to 3 dB) limited only by our electrical setup, for a
continuous-wave (CW) optical signal. Importantly, the device is linear with
respect to signal light. The observed contrast ratio is independent of the
timing, the format, the amplitude and the phase of the input signal.
