Novel attenuation-counter-propagating phase modulator for highly linear fiber-optic links

A key to the development of a high-dynamic-range phase-modulation fiber-optic link is a novel integrated photonic-phase-locked-loop (PPLL) linear phase demodulator, which consists of an inloop phase modulator and feedback control. At present, the propagation delay of the inloop phase modulator is the principal bottleneck in the implementation of this device. This paper specifically concerns a novel attenuation-counter-propagating (ACP) phase modulator (PM) that is free of propagation delay and therefore provides the solution. A rigorous theoretical model and an experimental verification of the ACP phase modulator were provided.