Extended Data Fig. 2: Setup of PDH locking and multi-frequency delayed self-heterodyne interferometer.
From: Microresonator-referenced soliton microcombs with zeptosecond-level timing noise
VCO: voltage-controlled oscillator; PM: phase modulator; AOFS: acousto-optic frequency shifters; PC: polarization controller; LO: local oscillator; BPF: optical bandpass filter; OSC: oscilloscope.
