Periodic Reporting for period 1 - TRIFFIC (Three-Dimensional Integrated Photonic-Phononic Circuit)
Reporting period: 2022-10-01 to 2025-03-31
The coherent optomechanical interaction between acoustic and optical waves known as stimulated Brillouin scattering (SBS) can enable ultra-high resolution signal processing and narrow linewidth lasers important for next-generation wireless communications, precision sensing, quantum information processing, and many more. But the proliferation of such a unique and powerful technology is currently impeded by fundamental challenges associated with circuit integration of Brillouin optomechanics in a versatile and mass producible material platform such as silicon nitride. The absence of acoustic guiding and the infinitesimal photo-elastic response of standard silicon nitride devices render conventional SBS in this material platform currently out of reach. An innovative approach that breaks with usual paradigms of actuating SBS solely through optical forces in two-dimensional waveguiding circuit is required to overcome these fundamental limitations.
The TRIFFIC project aims to actuate and functionalize SBS in silicon nitride through three-dimensional (3D) integration of gigahertz acoustic wave sources and waveguides with low loss optical circuits. The two orders of magnitude SBS gain enhancement expected from this project will unlock Brillouin optomechanics in silicon nitride circuits for the first time. Using this novel 3D optomechanical platform, I aim to demonstrate a revolutionary concept of on-demand and programmable optomechanics that will transform the field of RF photonics by providing an advanced signal processor with comprehensive spectral control beyond what is currently possible. Further, I will demonstrate Hz-linewidth integrated SBS lasers in the red and blue visible wavelengths that can be integrated with future portable optical atomic clocks and trapped-ion quantum computers.
The TRIFFIC project aims to actuate and functionalize SBS in silicon nitride through three-dimensional (3D) integration of gigahertz acoustic wave sources and waveguides with low loss optical circuits. The two orders of magnitude SBS gain enhancement expected from this project will unlock Brillouin optomechanics in silicon nitride circuits for the first time. Using this novel 3D optomechanical platform, I aim to demonstrate a revolutionary concept of on-demand and programmable optomechanics that will transform the field of RF photonics by providing an advanced signal processor with comprehensive spectral control beyond what is currently possible. Further, I will demonstrate Hz-linewidth integrated SBS lasers in the red and blue visible wavelengths that can be integrated with future portable optical atomic clocks and trapped-ion quantum computers.
Advancing Integrated Brillouin Photonics: We have achieved a series of groundbreaking advancements in integrated photonics, pushing the boundaries of device performance and functionality. By harnessing the transformative power of Brillouin photonics and integrating cutting-edge materials and platforms, we have developed solutions that stand to revolutionize optical communications, RF oscillators, and microwave photonic systems.
200x SBS Gain in TeO2-Silicon Nitride Waveguides
Integrating a tellurite (TeO2) layer with silicon nitride waveguides yielded a Brillouin gain of 81 m⁻¹W⁻¹-a 200-fold enhancement over standard silicon nitride platforms, enabling net amplification (5 dB, 3.4 ns delay). This also led to an ultracompact Brillouin laser, 2,000 times smaller than conventional designs with a 7 Hz RF linewidth, and tuneable microwave photonic notch filters (2.2 MHz resolution, 9 GHz range).
Strong SBS in Thin-Film Lithium Niobate (TFLN)
Demonstrated a Brillouin gain of 85 m⁻¹W⁻¹ with angle-dependent SBS control, enabling the first TFLN-based Brillouin laser (>20 nm tuning range, 9 Hz RF linewidth) and an all integrated microwave photonic notch filter combining SBS waveguides, modulators, and resonators.
Thermoelastic Surface Acoustic Waves (SAW)
Metallic grating emitters on TFLN actuated thermoelastic SAWs with modulation frequencies up to 6.58 GHz, enabling on-chip acousto-optic modulation.
Scalable Silicon Nitride Photonic Integrated Circuits
An in-house process for silicon nitride photonic devices achieved low propagation losses (<0.3 dB/cm) and intrinsic Q factors of 1 million, enabling high-volume manufacturing of low-loss silicon nitride photonic integrated circuits.
200x SBS Gain in TeO2-Silicon Nitride Waveguides
Integrating a tellurite (TeO2) layer with silicon nitride waveguides yielded a Brillouin gain of 81 m⁻¹W⁻¹-a 200-fold enhancement over standard silicon nitride platforms, enabling net amplification (5 dB, 3.4 ns delay). This also led to an ultracompact Brillouin laser, 2,000 times smaller than conventional designs with a 7 Hz RF linewidth, and tuneable microwave photonic notch filters (2.2 MHz resolution, 9 GHz range).
Strong SBS in Thin-Film Lithium Niobate (TFLN)
Demonstrated a Brillouin gain of 85 m⁻¹W⁻¹ with angle-dependent SBS control, enabling the first TFLN-based Brillouin laser (>20 nm tuning range, 9 Hz RF linewidth) and an all integrated microwave photonic notch filter combining SBS waveguides, modulators, and resonators.
Thermoelastic Surface Acoustic Waves (SAW)
Metallic grating emitters on TFLN actuated thermoelastic SAWs with modulation frequencies up to 6.58 GHz, enabling on-chip acousto-optic modulation.
Scalable Silicon Nitride Photonic Integrated Circuits
An in-house process for silicon nitride photonic devices achieved low propagation losses (<0.3 dB/cm) and intrinsic Q factors of 1 million, enabling high-volume manufacturing of low-loss silicon nitride photonic integrated circuits.
• Identified two highly scalable, non-suspended integrated photonic platforms capable of supporting Brillouin photonics, setting the stage for more robust and versatile device designs.
• Pioneered the first-ever on-chip fully integrated stimulated Brillouin lasers in highly scalable thin-film lithium niobate (TFLN) and tellurite-covered silicon nitride waveguides, unlocking new possibilities for integrated photonics.
• Engineered compact, narrow linewidth stimulated Brillouin lasers with Hz-level RF linewidths, delivering high-purity RF oscillators that push the limits of precision and stability.
• Developed a fully integrated solution on a TFLN platform, combining SBS spiral, on-chip modulator, and microring resonators, resulting in a powerful microwave photonic filter with unprecedented performance.
• Pioneered the first-ever on-chip fully integrated stimulated Brillouin lasers in highly scalable thin-film lithium niobate (TFLN) and tellurite-covered silicon nitride waveguides, unlocking new possibilities for integrated photonics.
• Engineered compact, narrow linewidth stimulated Brillouin lasers with Hz-level RF linewidths, delivering high-purity RF oscillators that push the limits of precision and stability.
• Developed a fully integrated solution on a TFLN platform, combining SBS spiral, on-chip modulator, and microring resonators, resulting in a powerful microwave photonic filter with unprecedented performance.