Showing papers by "Mario J. Paniccia published in 2021"

Hertz-linewidth semiconductor lasers using CMOS-ready ultra-high-Q microresonators

Abstract: Driven by narrow-linewidth bench-top lasers, coherent optical systems spanning optical communications, metrology and sensing provide unrivalled performance To transfer these capabilities from the laboratory to the real world, a key missing ingredient is a mass-produced integrated laser with superior coherence Here, we bridge conventional semiconductor lasers and coherent optical systems using CMOS-foundry-fabricated microresonators with a high Q factor of over 260 million and finesse over 42,000 A five-orders-of-magnitude noise reduction in the pump laser is demonstrated, enabling a frequency noise of 02 Hz2 Hz−1 to be achieved in an electrically pumped integrated laser, with a corresponding short-term linewidth of 12 Hz Moreover, the same configuration is shown to relieve the dispersion requirements for microcomb generation that have handicapped certain nonlinear platforms The simultaneous realization of this high Q factor, highly coherent lasers and frequency combs using foundry-based technologies paves the way for volume manufacturing of a wide range of coherent optical systems Using CMOS-ready ultra-high-Q microresonators, a highly coherent electrically pumped integrated laser with frequency noise of 02 Hz2 Hz−1, corresponding to a short-term linewidth of 12 Hz, is demonstrated The device configuration is also found to relieve the dispersion requirements for microcomb generation that have limited certain nonlinear platforms

Reaching fiber-laser coherence in integrated photonics.

Abstract: We self-injection-lock a diode laser to a 1.41 m long, ultra-high Q integrated resonator. The hybrid integrated laser reaches a frequency noise floor of 0.006Hz2/Hz at 4 MHz offset, corresponding to a Lorentzian linewidth below 40 mHz-a record among semiconductor lasers. It also exhibits exceptional stability at low-offset frequencies, with frequency noise of 200Hz2/Hz at 100 Hz offset. Such performance, realized in a system comprised entirely of integrated photonic chips, marks a milestone in the development of integrated photonics; and, for the first time, to the best of our knowledge, exceeds the frequency noise performance of commercially available, high-performance fiber lasers.

High-performance lasers for fully integrated silicon nitride photonics.

Abstract: Silicon nitride (SiN) waveguides with ultra-low optical loss enable integrated photonic applications including low noise, narrow linewidth lasers, chip-scale nonlinear photonics, and microwave photonics. Lasers are key components to SiN photonic integrated circuits (PICs), but are difficult to fully integrate with low-index SiN waveguides due to their large mismatch with the high-index III-V gain materials. The recent demonstration of multilayer heterogeneous integration provides a practical solution and enabled the first-generation of lasers fully integrated with SiN waveguides. However, a laser with high device yield and high output power at telecommunication wavelengths, where photonics applications are clustered, is still missing, hindered by large mode transition loss, non-optimized cavity design, and a complicated fabrication process. Here, we report high-performance lasers on SiN with tens of milliwatts output power through the SiN waveguide and sub-kHz fundamental linewidth, addressing all the aforementioned issues. We also show Hertz-level fundamental linewidth lasers are achievable with the developed integration techniques. These lasers, together with high-Q SiN resonators, mark a milestone towards a fully integrated low-noise silicon nitride photonics platform. This laser should find potential applications in LIDAR, microwave photonics and coherent optical communications.

Seamless multi-reticle photonics.

Abstract: While Moore’s law predicted shrinking transistors would enable exponential scaling of electronic circuits, the footprint of photonic components is limited by the wavelength of light. Thus, future high-complexity photonic integrated circuits (PICs) such as petabit-per-second transceivers, thousand-channel switches, and photonic quantum computers will require more area than a single reticle provides. In our novel approach, we overlay and widen waveguides in adjacent reticles to stitch a smooth transition between misaligned exposures. In SiN waveguides, we measure ultralow loss of 0.0004 dB per stitch, and produce a stitched delay line 23 m in length. We extend the design to silicon channel waveguides, and predict 50-fold lower loss or 50-fold smaller footprint versus a multimode-waveguide-based method. Our approach enables large-scale PICs to scale seamlessly beyond the single-reticle limit.

Self-regulating soliton domain walls in microresonators

Abstract: Dissipative soliton Kerr frequency combs in microresonators have recently been demonstrated with self-injection locking. They have the advantage of turnkey deterministic comb generation, and also simplify dark soliton generation in the normal dispersion regime. Here, the formation process of dark solitons triggered by self-injection locking is studied by regarding them as a pair of domain walls that connect domains having different intracavity powers. The self-injection locking mechanism allows the domain walls to self-regulate position so that a wide range of dark soliton states can be accessed. Moreover, soliton duty cycle is readily controlled by the feedback phase. Direct imaging of the dark soliton pulse shape using the electro-optic sampling technique is used to verify the theory. The results provide new physical insights as well as a new operational modality for this important class of nonlinear waves.

Hertz-level-linewidth semiconductor laser via injection locking to an ultra-high Q silicon nitride microresonator

Abstract: A conventional semiconductor DFB laser is self-injection-locked to a CMOS-foundryfabricated ultra-high Q silicon nitride microresonator, suppressing high-offset frequency noise to 0.2 Hz2 Hz-1 and yielding instantaneous linewidth of 1.2 Hz.

Formation Dynamics and Snapshots of Self-injection-locking Dark Solitons

Abstract: We propose a model for understanding dark solitons formation dynamics in self-injection-locking laser-resonator systems using dynamical instabilities and domain walls. Snapshots of solitons are captured with dual-comb imaging techniques and validate the model.