An optical phase modulator includes a bandpass multilayer stack, formed by a
plurality
of dielectric layers, preferably of GaAs and AlAs, and having a transmission function
related to the refractive index of the layers of the stack, for receiving an optical
input signal to be phase modulated. A phase modulator device produces a nonmechanical
change in the refractive index of each layer of the stack by, e.g., the injection
of free carrier, to provide shifting of the transmission function so as to produce
phase modulation of the optical input signal and to thereby produce a phase modulated
output signal.
