APL Photonics (Jun 2020)

Optical parametric gain in CMOS-compatible sub-100 μm photonic crystal waveguides

  • Ezgi Sahin,
  • Doris K. T. Ng,
  • Dawn T. H. Tan

DOI
https://doi.org/10.1063/5.0003633
Journal volume & issue
Vol. 5, no. 6
pp. 066108 – 066108-7

Abstract

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Emerging compositionally engineered complementary metal-oxide-semiconductor (CMOS)-compatible platforms have been employed for high efficiencies in various on-chip applications, including optical parametric amplification and wavelength conversion. Combining the novel nonlinear optics platforms such as ultra-silicon-rich nitride (USRN: Si7N3) with periodic waveguide structures can lead to further enhancement of material nonlinearities via the slow light effect and enable ultra-compact devices. Four-wave mixing in a USRN-based, CMOS-compatible, photonic crystal waveguide (PhCWg) leading to on/off optical parametric signal gain reaching 3 dB, and a large instantaneous idler conversion efficiency of −1 dB is explored experimentally. Enhancement of Kerr nonlinearity in the presence of a sizable and near-constant group index allows the findings on an ultra-compact, 97 μm-long PhCWg, equivalent to a large on/off gain per unit length of 333 dB/cm.