Layered 2D graphene oxide (GO) films are integrated with micro‐ring resonators (MRRs) to experimentally demonstrate enhanced nonlinear optics. Both uniformly coated (1−5 layers) and patterned (10−50 layers) GO films are integrated on complementary‐metal‐oxide‐semiconductor (CMOS)‐compatible doped silica MRRs using a large‐area, transfer‐free, layer‐by‐layer GO coating method with precise control of the film thickness. The patterned devices further employ photolithography and lift‐off processes to enable precise control of the film placement and coating length. Four‐wave‐mixing (FWM) measurements for different pump powers and resonant wavelengths show a significant improvement in efficiency of ≈7.6 dB for a uniformly coated device with 1 GO layer and ≈10.3 dB for a patterned device with 50 GO layers. The measurements agree well with theory, with the enhancement in FWM efficiency resulting from the high Kerr nonlinearity and low loss of the GO films combined with the strong light–matter interaction within the MRRs. The dependence of GO's third‐order nonlinearity on layer number and pump power is also extracted from the FWM measurements, revealing interesting physical insights about the evolution of the GO films from 2D monolayers to quasi bulk‐like behavior. These results confirm the high nonlinear optical performance of integrated photonic resonators incorporated with 2D layered GO films.
Layered two-dimensional (2D) graphene oxide (GO) films are integrated with silicon-on-insulator (SOI) nanowire waveguides to experimentally demonstrate an enhanced Kerr nonlinearity, observed through self-phase modulation (SPM). The GO films are integrated with SOI nanowires using a large-area, transfer-free, layer-by-layer coating method that yields precise control of the film thickness. The film placement and coating length are controlled by opening windows in the silica cladding of the SOI nanowires. Owing to the strong mode overlap between the SOI nanowires and the highly nonlinear GO films, the Kerr nonlinearity of the hybrid waveguides is significantly enhanced. Detailed SPM measurements using picosecond optical pulses show significant spectral broadening enhancement for SOI nanowires coated with 2.2 mm long films of 1–3 layers of GO and 0.4 mm long films with 5–20 layers of GO. By fitting the experimental results with theory, the dependence of GO’s Kerr nonlinearity on layer number and pulse energy is obtained, showing interesting physical insights and trends of the layered GO films from 2D monolayers to quasi bulk-like behavior. Finally, we show that by coating SOI nanowires with GO films, the effective nonlinear parameter of SOI nanowires is increased 16-fold, with the effective nonlinear figure of merit (FOM) increasing by about 20 times to FOM > 5. These results reveal the strong potential of using layered GO films to improve the Kerr nonlinear optical performance of silicon photonic devices.
superior performance with respect to speed and operation bandwidth than electronic based devices. [3-5] As a fundamental χ (3) process, FWM has found a wide range of applications in wavelength conversion, [6,7] optical frequency comb generation, [8,9] optical sampling, [10,11] quantum entanglement, [12,13] and many others. [14,15] Implementing nonlinear photonic devices in integrated form offers the greatest dividend in terms of compact footprint, high stability, high scalability, and mass-producibility. [1,2,16] Although silicon has been a leading platform for integrated photonic devices for many reasons, [1] including the fact that it leverages the well-developed complementary metal-oxide-semiconductor (CMOS) fabrication technologies, [17] its strong twophoton absorption (TPA) at near-infrared telecommunications wavelengths poses a fundamental limitation for devices operating in this wavelength region. Other CMOS compatible platforms such as silicon nitride (SiN) and doped silica [2,18] have a much lower TPA, although they still suffer from intrinsic limitation arising from a much lower Kerr nonlinearity. The increasing demand for high performing nonlinear integrated photonic devices has motivated the search for highly
With superior optical properties, high flexibility in engineering its material properties, and strong capability for large‐scale on‐chip integration, graphene oxide (GO) is an attractive solution for on‐chip integration of 2D materials to implement functional integrated photonic devices capable of new features. Over the past decade, integrated GO photonics, representing an innovative merging of integrated photonic devices and thin GO films, has experienced significant development, leading to a surge in many applications covering almost every field of optical sciences such as photovoltaics, optical imaging, sensing, nonlinear optics, and light emitting. This paper reviews the recent advances in this emerging field, providing an overview of the optical properties of GO as well as methods for the on‐chip integration of GO. The main achievements made in GO hybrid integrated photonic devices for diverse applications are summarized. The open challenges as well as the potential for future improvement are also discussed.
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.
hi@scite.ai
10624 S. Eastern Ave., Ste. A-614
Henderson, NV 89052, USA
Copyright © 2024 scite LLC. All rights reserved.
Made with 💙 for researchers
Part of the Research Solutions Family.