Fig. 3: Highly confining X-cut and Z-cut LiNbO3 photonic integrated microresonator characterization.
From: High density lithium niobate photonic integrated circuits
a The most probable value κ0/2π of 9 chips measured on each of the fields shown on the 100 mm (4 in.) wafer. The reticle design contains 16 chips in each of the 9 fields uniformly exposed over the x-cut LiNbO3 wafer. b Microresonator transmission (blue) and linewidth measurement of a single resonance at 192.97 THz from the racetrack resonator with 3 μm width waveguide using frequency-comb-assisted diode laser spectroscopy results in κ0/2π = 18.2 MHz. c Histogram of TE00 resonances from a 2 μm (red) and 3 μm (blue) wide single racetrack x-cut LiNbO3 resonator showing the most probable value of κ0/2π = 45 MHz. d SEM image of microresonator with a radius of 20 μm from a z-cut LiNbO3 wafer (corresponding to a ca. 1 THz FSR). e Measured integrated dispersion of the x-cut LiNbO3 microresonator with free spectral range about 81 GHz, anomalous dispersion D2/2π = 105.72 kHz for 2 μm waveguide width microresonator and normal dispersion of D2/2π = −291.23 kHz for 3 μm waveguide width. Histograms of intrinsic cavity linewidths for TE00 resonances of z-cut LiNbO3 microresonators with FSRs of (f) 102 GHz, (g) 504 GHz, (h) 967 GHz. i Intrinsic cavity linewidth vs free spectral range of the microresonators. Red circles show the mean values from distributions in (f, g, h). Vertical bars show min and max values.
