SiC photonics has been developed for over a decade, one of the major
obstacles is the difficulty of fabricating ultralow optical loss SiC
thin-films. Scientists in China have fabricated an ultralow loss 4H-SiCOI
platform with a record-high-Q factor of 7.1 × 106. Nonlinear
photonics process, including second-, third- and fourth-harmonic
generations, Raman lasing, and Kerr frequency combs have been observed. This
demonstration represents a milestone in the development of SiC photonic
devices.
Photonic integrated circuits (PICs) and microresonators have attracted
strong interest in photonics community. For applications, achieving low
optical loss is crucial. SiC PICs have been in development for over a
decade, a lot of works have been carried out on the SiC thin films prepared
by heteroepitaxial growth. However, the quality factor of these devices is
limited to less than 106 due to the high density of crystal defects near
growth interface. Up to now, how to further reduce the optical loss of SiC
thin films has become the primary problem for scientist to explore the
advantages of SiC in PICs applications.
In a new paper published in Light Science & Application, a team of
scientists, led by Professor Xin Ou from State Key Laboratory of Functional
Materials for Informatics, Shanghai Institute of Microsystem and Information
Technology, Chinese Academy of Sciences, and co-workers have fabricated an
ultralow loss 4H-SiCOI platform with a record-high-Q factor of 7.1 ×
106. The 4H-SiCOI platform prepared by wafer-bonding than
thinning techniques, enables the same crystalline quality as bulk high-pure
4H-SiC crystal. The high Q resonators were used to demonstrate various
nonlinear processes including generation of multiple harmonics up to the
fourth order, cascaded Raman lasing, and Kerr frequency comb. Broadband
frequency conversions, including second-, third-, fourth- harmonic
generation (SHG, THG, FHG) have been observed. Cascaded Raman lasing with
Raman shift of 204.03 cm-1 has been demonstrated in SiC microresonators for
the first time. Using a dispersion-engineered SiC microresonator, Kerr
frequency combs covering from 1300 to 1700 nm have been achieved at a low
input power of 13 mW.
The demonstration of high Q SiC photonics devices represents a significant
milestone in the development of SiC PICs. This work was also highly praised
by the reviewers. "In my opinion, this work is novel, sound and important. I
believe this work will bring a huge momentum for SiC integrated photonics in
the next few years", "I believe this work will be a milestone for SiC
photonics", "The presented work here shows microresonator with Q up to 7.1 ×
106, which is certainly a major breakthrough in the development
of photonic devices that harness the unique optical properties of SiC".
Reference:
Chengli Wang et al, High-Q microresonators on 4H-silicon-carbide-on-insulator
platform for nonlinear photonics, Light: Science & Applications (2021).
DOI: 10.1038/s41377-021-00584-9
Tags:
Physics