Broadband quasi-phase-matched optical parametric generation in phase reversal optical superlattice devices

We have theoretically investigated the generation of ultra-flat broadband optical parametric generation (OPG) in the communication band using a lithium niobate based domain engineered phase reversal optical superlattice (PROS) structure by group velocity matching (GVM) technique. The simulation results show an ultra-flat broadband OPG of acceptance FWHM bandwidth Delta lambda = 210 nm centered at 1.55 mu m in 10 mm long device with 19 mu m period operating at 20 degrees C for 775 nm fixed pump wavelength. The selection of the period and pump wavelength relies on the group velocities of the signal and idler wavelengths close to zero-group velocity dispersion (GVD) point to achieve broadband OPG. The PROS quasi-phase matching (QPM) device generates broader and ultra-flat OPG compared to the conventional periodic QPM counterparts. Further, the variation in the flatness of the broadband QPG due to the change in the location and width of the phase reversal (PR) domain in the device is discussed.