Wideband OPLL photonic integrated circuit enabling ultrahigh dynamic range PM RF/photonic ink

The RF/photonic link is the basic element of microwave photonics. Previous RF photonic links often rely on optical intensity modulation. The inherent modulation nonlinearity leads to inadequate spurious free dynamic range (SFDR) for many sought-after microwave photonic applications in radar. A new phase-modulated (PM) link with an optical phase-locked loop (OPLL) demodulator could afford a promising solution for the SFDR. However, the efficacy of the PM link approach remained unsubstantiated as previous OPLL implementations had too restricted of a bandwidth for realistic applications. Here, we present a new OPLL photonic integrated circuit (PIC) chip that offered quadrupled bandwidth enhancement over the state of the art. The OPLL PIC represents the first OPLL linear optical phase demodulator with sufficient bandwidth for realistic microwave photonic applications. With help of the OPLL PIC, a PM RF/photonic link demonstrated a record-breaking SFDR of similar to 129.3 dB . Hz(2/3) and a 3 dB SFDR bandwidth of similar to 1 GHz. The combined SFDR and bandwidth performance amounts to around 1 order of magnitude improvement over the prior state of the art. (C) 2019 Optical Society of America under the terms of the OSA Open Access Publishing Agreement