Photonics Research, Volume. 10, Issue 5, 05001290(2022)

Soliton frequency comb generation in CMOS-compatible silicon nitride microresonators

Yaozu Xie1, Jiaqi Li1, Yanfeng Zhang1,2,*, Zeru Wu1, Shihao Zeng1, Shuqing Lin1, Zhaoyang Wu1, Wenchao Zhou1, Yujie Chen1, and Siyuan Yu1,3,*
Author Affiliations
  • 1State Key Laboratory of Optoelectronic Materials and Technologies, School of Electronics and Information Technology, Sun Yat-sen University, Guangzhou 510275, China
  • 2e-mail:
  • 3e-mail:
  • show less

    The monolithic integration of soliton microcomb devices with active photonic components and high-frequency electronics is highly desirable for practical applications. Among many materials, silicon nitride (SiNx) waveguide layers prepared by low-pressure chemical vapor deposition (LPCVD) have been the main platform for on-chip optical frequency comb generation. However, the high temperatures involved in LPCVD render it incompatible as a back-end process with complementary metal oxide semiconductor (CMOS) or active III-V compound semiconductor fabrication flows. We report the generation of coherent soliton frequency combs in micro-ring resonators fabricated in deuterated silicon nitride (SiNx:D) waveguides with a loss of 0.09 dB/cm. Deposited at 270°C by an inductance-coupled plasma chemical vapor deposition (ICP-CVD) process, the material preparation and fabrication flow are fully CMOS-compatible. These results enable the integration of silicon-nitride-based optical combs and photonic integrated circuits (PICs) on prefabricated CMOS and/or III-V substrates, therefore marking a major step forward in SiNx photonic technologies.


    On-chip optical frequency combs could revolutionize a vast range of applications such as optical atomic clocks [1], astronomy [2,3], coherent optical communication [4,5], ultrafast distance measurements by means of LIDAR [69], spectroscopy [10], and integrated microwave photonics [11,12]. It could also be applied in optical neural computing [13,14] and quantum optics [15,16]. Silicon nitride (SiNx) has been the main platform for optical comb generation by way of Kerr nonlinearity as the material combines the lowest linear loss with a relatively high refractive index and strong Kerr effect among many material platforms [17]. SiNx is widely used in microelectronic and photonic fabrication flows, making it a readily acceptable candidate for monolithic integration with active photonic components and high-frequency electronics, which would be key to the practical applications of optical comb sources.


    Get Citation

    Copy Citation Text

    Yaozu Xie, Jiaqi Li, Yanfeng Zhang, Zeru Wu, Shihao Zeng, Shuqing Lin, Zhaoyang Wu, Wenchao Zhou, Yujie Chen, Siyuan Yu. Soliton frequency comb generation in CMOS-compatible silicon nitride microresonators[J]. Photonics Research, 2022, 10(5): 05001290

    Download Citation

    EndNote(RIS)BibTexPlain Text
    Save article for my favorites
    Paper Information

    Category: Integrated Optics

    Received: Jan. 27, 2022

    Accepted: Mar. 17, 2022

    Published Online: Apr. 27, 2022

    The Author Email: Yanfeng Zhang (, Siyuan Yu (



    Please enter the answer below before you can view the full text.