Fig. 1 | Nature Communications

Fig. 1

From: Large second harmonic generation enhancement in Si3N4 waveguides by all-optically induced quasi-phase-matching

Fig. 1

Experimental setup and waveguides. a Experimental set-up. TLS, tuneable laser source; MZM, Mach-Zehnder modulator; EDFA, erbium-doped fibre amplifier; BPF, fibre band pass filter; LF, lensed fibre; CCD, digital camera; BF, free-space block filter assembly; PD, power detector; SH, second harmonic; TH, third harmonic. b Pump (magenta line) and second harmonic (blue line) spectra at the waveguide output for a coupled peak power of 90 W, after the second harmonic growth. No significant pump broadening is observed. c Scanning electron microscope picture of a waveguide cross-section (scale bar: 0.5 μm). d Simulation of the pump profile, injected on the fundamental transverse magnetic mode

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