Fig. 3: Adapted poling DFG efficiency measurement.
From: Integrated broadband and high-efficiency difference frequency generation
a Optical microscope image of waveguide facets. b The measured PFM signal of the periodical ferroelectric domain inversion in the thin-film PPLN waveguide. c SEM image of a waveguide facet. d Experimental setup for DFG characterization. e Captured image of the chip in the DFG experiment. f Measured spectrum of signal and idler waves. g Simulated (line) and measured (dots) normalized CEs of DFG at different temperatures. TEC, thermoelectric cooler. PD, photodetector. PC, polarization controller. WDM, wavelength division multiplexer.
