@article{xue_palmese_sekely_little_kish_muth_wierer_2024, title={Growth and characterization of AlInN/GaN superlattices}, volume={630}, ISSN={["1873-5002"]}, url={https://doi.org/10.1016/j.jcrysgro.2024.127567}, DOI={10.1016/j.jcrysgro.2024.127567}, abstractNote={Data are presented on near-lattice-matched Al1-xInxN/GaN superlattices (SLs) with superior morphology to thick AlInN layers. The SLs are grown by metalorganic chemical vapor deposition and consist of ∼3 nm thick AlInN, ∼1 nm thick GaN layers, and x=0.153 to 0.203. The SLs are grown with either 20 or 100 periods on GaN-on-sapphire or free-standing GaN substrates. Growth conditions are explored, and the In-content of the AlInN layers within the SL increases with growth temperature and pressure, while the growth rate decreases with pressure. Thick AlInN layers grown on GaN-on-sapphire exhibit island growth with a root mean square (rms) roughness of ∼0.65 nm, while the AlInN/GaN SLs have steplike morphology and rms ∼0.3 nm. Also, 80 nm thick AlInN/GaN SLs grown on GaN substrates exhibit nearly perfect steplike morphology with a lower rms of ∼0.13 nm and extremely low pit densities. The refractive index of the SLs is the weighted average of AlInN and GaN, and they emit light from the quantum states within the thin GaN layers. These AlInN/GaN SLs are a potential replacement for AlInN layers in optoelectronic and electronic devices that require steplike morphology and controlled pitting.}, journal={JOURNAL OF CRYSTAL GROWTH}, author={Xue, Haotian and Palmese, Elia and Sekely, Ben J. and Little, Brian D. and Kish, Fred A. and Muth, John F. and Wierer, Jonathan J.}, year={2024}, month={Mar} }
 @article{mckinzie_wang_al noman_mathine_han_leaird_hoefler_lal_kish_qi_et al._2021, title={InP high power monolithically integrated widely tunable laser and SOA array for hybrid integration}, volume={29}, ISSN={["1094-4087"]}, DOI={10.1364/OE.413434}, abstractNote={We present a monolithic InP-based photonic integrated circuit (PIC) consisting of a widely tunable laser master oscillator feeding an array of integrated semiconductor optical amplifiers that are interferometrically combined on-chip in a single-mode waveguide. We demonstrate a stable and efficient on-chip coherent beam combination and obtain up to 240 mW average power from the monolithic PIC, with 30–50 kHz Schawlow-Townes linewidths and >180 mW average power across the extended C-band. We also explored hybrid integration of the InP-based laser and amplifier array PIC with a high quality factor silicon nitride microring resonator. We observe lasing based on gain from the interferometrically combined amplifier array in an external cavity formed via feedback from the silicon nitride microresonator chip; this configuration results in narrowing of the Schawlow-Townes linewidth to ∼3 kHz with 37.9 mW average power at the SiN output facet. This work demonstrates a new approach toward high power, narrow linewidth sources that can be integrated with on-chip single-mode waveguide platforms for potential applications in nonlinear integrated photonics.}, number={3}, journal={OPTICS EXPRESS}, author={McKinzie, Keith A. and Wang, Cong and Al Noman, Abdullah and Mathine, David L. and Han, Kyunghun and Leaird, Daniel E. and Hoefler, Gloria E. and Lal, Vikrant and Kish, Fred and Qi, Minghao and et al.}, year={2021}, month={Feb}, pages={3490–3502} }
 @article{bhardwaj_bustos-ramirez_hoefler_dentai_plascak_kish_delfyett_wu_2020, title={A Monolithically Integrated Racetrack Colliding-Pulse Mode-Locked Laser With Pulse-Picking Modulator}, volume={56}, ISSN={["1558-1713"]}, DOI={10.1109/JQE.2020.2994990}, abstractNote={We present a novel photonic integrated circuit (PIC) that monolithically integrates a racetrack colliding-pulse mode-locked laser with a pulse-picking electro-absorption modulator and a semiconductor optical amplifier on Indium Phosphide. We present detailed characterization of this PIC that includes optical pulse characterization, phase noise and long term stability under passive and hybrid mode-locking conditions. Allan deviation measurements made on the optical pulse train from the PIC show a fractional frequency instability of <inline-formula> <tex-math notation="LaTeX">$8\times 10 ^{-11}$ </tex-math></inline-formula> at 1 second and follow a 1/<inline-formula> <tex-math notation="LaTeX">$\tau $ </tex-math></inline-formula> trend. We also demonstrate repetition rate reduction from ~10 GHz to ~500 MHz with an extinction ratio of ~14.65 dB using an on-chip pulse-picking electro-absorption modulator.}, number={4}, journal={IEEE JOURNAL OF QUANTUM ELECTRONICS}, author={Bhardwaj, Ashish and Bustos-Ramirez, Ricardo and Hoefler, Gloria E. and Dentai, Andrew and Plascak, Michael E. and Kish, Fred and Delfyett, Peter J. and Wu, Ming C.}, year={2020}, month={Aug} }