Recent work on milestones and difficulties in silicon carbide (SiC)-based integrated optics has been thoroughly investigated by scientists under the direction of Xin Ou from the Shanghai Institute of Microsystem and Information Technology (SIMIT) of the Chinese Academy of Sciences. The journal Applied Physics Reviews released this review.
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Illustration of single crystal 4H-SiC and Kerr comb generation. Image Credit: Light: Science & Applications
Two information technology bottlenecks—transmission bandwidth and processing speed—are anticipated to be resolved by photonic integrated circuits (PICs). Conventional silicon photonics, however, are unable to implement every function needed by society.
Platforms like LiNbO3, Si3N4, etc., are investigated as supplements. SiC is seen as a viable platform for PICs in particular due to its high refractive index, large transparency window, high nonlinear coefficient, affinity with complementary metal oxide semiconductors (CMOS), etc.
The last three years have seen the sequential demonstrations of ultra-high Q (maximum value 7.1×106) SiC optical resonators, octave-spanning Kerr frequency micro combs, and soliton Kerr frequency micro combs at cryogenic temperatures. A microring-based electro-optical modulator with a high optical density was developed in electro-optics. In quantum optics, SiC is also given a lot of consideration.
One spin flaw with bright emission and a lengthy spin coherence time can be hosted by it. It has been achieved to coherently manipulate a single divacancy spin in 4H-SiC and to efficiently couple silicon vacancies (SiV) to resonators (micro-pillars or PhCs) in 4H-SiCOI.
Additionally, the waveguide was included with a cubic lattice site SiV (V2) produced by He+ implantation without suffering any loss of inherent spin-optical characteristics.
SiC photonics is currently experiencing great growth with both opportunities and difficulties, particularly in the production of high-quality silicon carbide-on-insulator (SiCOI).
SiCOI-based incorporated photonics has been the subject of systematic research by the SIMIT team at OU.
In 2019, they used ion-cutting technology to build a 4-inch, very consistent 4H-SiCOI for integrated optics, and they used H+ implantation to create a room-temperature coherent controllable spin flaw in the 4H-SiC.
A SiC resonator was subsequently created using a femtosecond laser-assisted chemical-mechanical polishing technique, and its optical quality factor was found to be 7.1×106, the highest value yet recorded in SiC photonics.
Wideband Kerr frequency, cascaded Raman lasing, and broadband frequency conversion were made possible by the ultrahigh-Q. InGaAs quantum dot-based single-photon sources were connected with a 4H-SiC photonic chip using the pick-and-place method in 2022.
The creation and extremely effective routing of single-photon emission in the hybrid quantum photonic chip was made possible by building bilayer vertical couplers and 1×2 multimode interferometers with a power-splitting ratio of 50:50.
Recently, the team set out to create broadband wide soliton frequency Kerr combs with minimal optical loss and to enable combined nonlinear and quantum SiC photonics.
SiC integrated optics might be anticipated to have a wider future in light of the developments in SiC nonlinear and quantum optics. Nonlinear and quantum optics, as well as SiC power and radio frequency systems, will all be driven by the creation of low-cost, wafer-scale, and high-quality 4H-SiCOI.
Journal Reference
Yi, A., et al. (2022) Silicon carbide for integrated photonics. Applied Physics Reviews. https://doi.org/10.1063/5.0079649.