Fig. 4: Electro-optic frequency comb generation and tunable photonic dimers.
From: A heterogeneously integrated lithium niobate-on-silicon nitride photonic platform
a Experimental setup for electro-optic frequency comb generation. MWG - microwave generator, MWA - microwave amplifier, OSA - optical spectrum analyzer. b Mode coupling schematic and integrated dispersion of the device. c Measured optical spectrum of the generated electro-optic comb with a central frequency of 1552 nm. The dashed line corresponds to numerical simulations with phase modulation amplitude β = 0.14π. d Examples of electro-optic frequency combs generated at four other pump wavelengths. e Photonic dimer image and illustration of mode hybridization. f Splitting of high-Q resonances in a photonic dimer without additional biasing. S - symmetric supermode, AS - antisymmetric supermode. g DC tuning of the photonic dimer mode hybridization, corresponding to linear tuning of around 30 MHz/V for a single mode. h Echelle-type spectrogram of the photonic dimer transmission, showing mode hybridization over a broad scanning range.
