Alexander S. Gorodnitskiy

The original version of this Article contained an error in the first sentence of the Acknowledgements, which incorrectly read ‘This publication was supported by Contract HR0011-15-C-0055 (DODOS) from the Defense Advanced Research Projects Agency (DARPA), Defense Sciences Office (DSO).’ The correct version states ‘Microsystems Technology Office (MTO)’ in place of ‘Defense Sciences Office (DSO)’. This has been corrected in both the PDF and HTML versions of the Article.

Microcombs provide a path to broad-bandwidth integrated frequency combs with low power consumption, which are compatible with wafer-scale fabrication. Yet, electrically-driven, photonic chip-based microcombs are inhibited by the required high threshold power and the frequency agility of the laser for soliton initiation. Here we demonstrate an electrically-driven soliton microcomb by coupling a III–V-material-based (indium phosphide) multiple-longitudinal-mode laser diode chip to a high-Q silicon nitride microresonator fabricated using the photonic Damascene process. The laser diode is self-injection locked to the microresonator, which is accompanied by the narrowing of the laser linewidth, and the simultaneous formation of dissipative Kerr solitons. By tuning the laser diode current, we observe transitions from modulation instability, breather solitons, to single-soliton states. The system operating at an electronically-detectable sub-100-GHz mode spacing requires less than 1 Watt of electrical power, can fit in a volume of ca. 1 cm³, and does not require on-chip filters and heaters, thus simplifying the integrated microcomb.

We present a novel method allowing high-power single-frequency emission with sub-kHz linewidth from a compact multi-frequency diode laser locked to high-Q optical microresonator. Using high-Q MgF₂microresonator and multi-frequency diode laser operating at 1535 nm with the output power of 100 mW and an emission spectrum consisting of approximately 50 lines with MHz linewidth, we observed a spectrum collapse to a single line or several lines with a sub-kHz linewidth and output power power of 50 mW. The Bogatov effect predicted more than 30 years ago was observed and studied in the spectrum of the locked laser. For analysis of the considered effect, original theoretical model taking into account self-injection locking effect, mode competition and Bogatov asymmetric mode interaction was developed and numerical modeling was performed. All numerical results are in a good agreement with our experimental data. Accurate analytical estimations for the parameters critical for the considered effect were obtained. The proposed method may be applied for different types of diode lasers operating in different spectral ranges.

We report an experimental investigation of electro-optic amplitude modulator based on whispering gallery mode (WGM) optical microresonators. We have analyzed in detail the limits of operating ranges and ways to extend them. The WGM resonator is a polished lithium niobate micro-disk with metal deposited ring RF electrodes. To excite the WGM modes, a coupling prism was used.

The experimental study of the InP laser diode stabilization by high-Q Si 3 N 4 microresonator is presented. We demonstrate how this stabilized laser diode considered as a pump laser may be used for optical frequency comb generation in the same microresonator. Various properties of the stabilized laser linewidth and the optical frequency comb are measured.

We demonstrate theory and experiment of transformation of a ordinary multi-frequency Fabry-Perot laser diode spectrum to a single-frequency ultra-narrow-linewidth and coherent low noise soliton Kerr frequency combs source via self-injection locking to an optical microresonator.

Kerr frequency comb generated in ultra-high Q whispering gallery mode (WGM) microresonators is a promising light source for ultra-compact photonic devices due to its potential advantages of low power consumption and possibility of chip integration. We introduce a technique to stabilize and control effective generation of dissipative Kerr solitons (DKS) in nonlinear crystalline microresonators using regular commercial broad spectrum multi-frequency CW laser diodes (1550 nm; P ~ 200 mW), self-injection locked to magnesium fluoride microresonators (Q > 109).