Abstract
CMOS platforms operating at the telecommunications wavelength either reside within the highly dissipative two-photon regime in silicon-based optical devices, or possess small nonlinearities. Bandgap engineering of non-stoichiometric silicon nitride using state-of-the-art fabrication techniques has led to our development of USRN (ultra-silicon-rich nitride) in the form of Si
7
N
3
, that possesses a high Kerr nonlinearity (2.8 × 10
−13
cm
2
W
−1
), an order of magnitude larger than that in stoichiometric silicon nitride. Here we experimentally demonstrate high-gain optical parametric amplification using USRN, which is compositionally tailored such that the 1,550 nm wavelength resides above the two-photon absorption edge, while still possessing large nonlinearities. Optical parametric gain of 42.5 dB, as well as cascaded four-wave mixing with gain down to the third idler is observed and attributed to the high photon efficiency achieved through operating above the two-photon absorption edge, representing one of the largest optical parametric gains to date on a CMOS platform.
Typical CMOS materials in the telecommunications band suffer from two-photon absorption or possess weak Kerr nonlinearities. Here, Ooi
et al
. demonstrate 42.5 dB optical parametric amplification in ultra-silicon-rich nitride waveguides, designed to have strong nonlinearities with negligible losses.