Design of spontaneous parametric down-conversion in integrated hybrid Si_xN_y-PPLN waveguides

Abstract

High-efficient and high-purity photon sources are highly desired for quantum information processing. We report the design of a chip-scale hybrid SixNy and thin film periodically-poled lithium niobate waveguide for generating high-purity type-II spontaneous parametric down conversion (SPDC) photons in telecommunication band. The modeled second harmonic generation efficiency of 225% W -1 • cm -2 is obtained at 1560nm. Joint spectral analysis is performed to estimate the frequency correlation of SPDC photons, yielding intrinsic purity with up to 95.17%. The generation rate of these high-purity photon pairs is estimated to be 2.87 × 10 7 pairs/s/mW within the bandwidth of SPDC. Our chip-scale hybrid waveguide design has the potential for large scale on-chip quantum information processing and integrated photon-efficient quantum key distribution through high-dimensional time-energy encoding.

Investigation of 1064-nm Pumped Type II SPDC in Potassium Niobate for Generation of High Spectral Purity Photon Pairs

“…LN is "nonlinear optically" different from KN in that it belongs to the trigonal 3 m point group and exhibits uniaxial birefringence. Several studies on the photon-pair generation using PPLNs have been reported so far, but in all of the cases the EPM approach was not used or the frequencies of the generated photon pairs were not degenerated [30][31][32][33][34]. Experimental results for the generation of photon pairs in thin-film PPLN have only been reported recently, but again, Type 0 SPDC were used [35,36].…”

Mid-infrared spectrally-uncorrelated biphotons generation from doped PPLN: a theoretical investigation

“…In the future, it is promising to explore more LN crystals doped with different chemical elements and with different doping ratios. Another promising direction is investigating the spectrally pure single-photon state generation from doped PPLN waveguide [59][60][61] or doped PPLN film [62], which has the merits of higher nonlinear efficiency, easier for integration and microminiaturization. In Fig.…”

Study of Type II SPDC in Lithium Niobate for High Spectral Purity Photon Pair Generation

“…The experimentally reported brightness values are 6 × 10 5 /s/GHz and 3 × 10 5 /s/GHz for non-diffused and Ti-indiffused PPLN waveguides, respectively [26,27]. The rates of photon-pair generation are 1.2 × 10 3 pairs/s/mW and 2.87 × 10 7 pairs/s/mW for a bulk PPLN and hybrid PPLN waveguide, respectively [28,29]. Experimental results for the generation of photon pairs in thin-film PPLN have only been reported recently, where Type 0 SPDC were used [31,32].…”

“…In addition, the extended phase matching (EPM) is defined as when group velocity (GV) matching is additionally achieved between photons interacting under Type II SPDC, where high-purity photon pairs can be generated in a wide bandwidth [21][22][23][24][25]. Several studies on the photon-pair generation based on Type II SPDC in PPLN waveguides have been reported so far, but in all cases the EPM scheme was not used or the frequencies of the generated photon pairs were not identical to each other [26][27][28][29][30]. The experimentally reported brightness values are 6 × 10 5 /s/GHz and 3 × 10 5 /s/GHz for non-diffused and Ti-indiffused PPLN waveguides, respectively [26,27].…”