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 Si7N3, that possesses a high Kerr nonlinearity (2.8 × 10−13 cm2 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.

A cladding-modulated 1D photonic crystal is realized for creating ultra-large dispersion on a silicon chip. Both normal dispersion and anomalous dispersion are realized on the same waveguide device. The design, fabrication, and characterization of the devices are demonstrated. The device exploits adjacent pillars' positioning to engineer the dispersion, as well as the variation of the distance between the pillar and waveguide to realize apodization. Devices achieving a group delay dispersion coefficient of −3.61 ps/nm and 3.28 ps/nm are demonstrated with a footprint of 1.27 × 1.7 mm2. The demonstrated devices possess a group delay dispersion coefficient × bandwidth product as large as 72 ps on a silicon, CMOS-compatible chip.

Silicon carbide (SiC) is considered a promising platform for linear and nonlinear photonics due to its large band gap, large refractive index, low thermo-optic coefficient, large Kerr nonlinearity, and good mechanical stability. We evaluate amorphous SiC (a-SiC) deposited on an insulator, using plasma-enhanced chemical vapor deposition, as a nonlinear optical material. Deposited films possess a band gap of 2.3 eV and refractive index of 2.45 at a wavelength of 1550 nm. Ring resonators with intrinsic quality factor as high as 1.6 × 105 are demonstrated. Waveguides with loss as low as 3 dB/cm enable low loss linear integrated photonics. The Kerr nonlinearity of a-SiC around 1550 nm is measured to be 4.8 × 10–14 cm2/W1 order of magnitude higher than previous results measured for both crystalline and amorphous SiC. Nonlinear loss characterization shows that two-photon absorption is absent. The three-photon absorption coefficient is characterized to be ∼0.01 cm3/GW2. The strong Kerr nonlinearity makes a-SiC a great platform for CMOS-compatible nonlinear photonics.

The rapid development of graphene has opened up exciting new fields in graphene plasmonics and nonlinear optics. Graphene's unique twodimensional band structure provides extraordinary linear and nonlinear optical properties, which have led to extreme optical confinement in graphene plasmonics and ultrahigh nonlinear optical coefficients, respectively. The synergy between graphene's linear and nonlinear optical properties gave rise to nonlinear graphene plasmonics, which greatly augments graphene-based nonlinear device performance beyond a billion-fold. This nascent field of research will eventually find far-reaching revolutionary technological applications that require device miniaturization, low power consumption and a broad range of operating wavelengths approaching the far-infrared, such as optical computing, medical instrumentation and security applications.

The three-dimensional Dirac semimetal (3D DSM) is a new class of material with a slew of electronic and optical properties in common with graphene, while structurally having a bulk form like real metals. In particular, the Dirac band structure of 3D DSM conferred very high optical nonlinearities much like the case for graphene. Consequently, we found that 3D DSM has respectable nonlinear plasmonic performance in comparison with graphene, while retaining the structural benefits of bulk metals, having reduced passive plasmonic losses, and is much easier to handle in fabrication facilities. 3D DSM is expected to play a strong role in providing strong optical nonlinearities for all-optical switching and at the same time offering a superior platform for nanophotonic device integration.