Bandpass Attenuating-Counter-Propagating Phase Modulator

Attenuating-counter-propagating (ACP) phase modulators enable wideband optical phase-locked loop (OPLL) phase demodulator for high dynamic range RF/photonic links. However, existing ACP modulators have low-pass response that limits the OPLL operating frequency. In this letter, we present the first bandpass ACP phase modulator realized on an LiNbO 3 substrate employing a novel periodically bended optical waveguide structure. The device demonstrated latency free phase modulation centered at 7 GHz.