Hybrid InP and SiN integration of an octave-spanning frequency comb
Travis C. Briles,
Su-Peng Yu,
Lin Chang,
Chao Xiang,
Joel Guo,
David Kinghorn,
Gregory Moille,
Kartik Srinivasan,
John E. Bowers,
Scott B. Papp
Affiliations
Travis C. Briles
Time and Frequency Division, Physical Measurement Laboratory, National Institute of Standards and Technology, Boulder, Colorado 80305, USA
Su-Peng Yu
Time and Frequency Division, Physical Measurement Laboratory, National Institute of Standards and Technology, Boulder, Colorado 80305, USA
Lin Chang
ECE Department, University of California Santa Barbara, Santa Barbara, California 93106, USA
Chao Xiang
ECE Department, University of California Santa Barbara, Santa Barbara, California 93106, USA
Joel Guo
ECE Department, University of California Santa Barbara, Santa Barbara, California 93106, USA
David Kinghorn
ECE Department, University of California Santa Barbara, Santa Barbara, California 93106, USA
Gregory Moille
Microsystems and Nanotechnology Division, Physical Measurement Laboratory, National Institute of Standards and Technology, Gaithersburg, Maryland 20899-6203, USA
Kartik Srinivasan
Microsystems and Nanotechnology Division, Physical Measurement Laboratory, National Institute of Standards and Technology, Gaithersburg, Maryland 20899-6203, USA
John E. Bowers
ECE Department, University of California Santa Barbara, Santa Barbara, California 93106, USA
Scott B. Papp
Time and Frequency Division, Physical Measurement Laboratory, National Institute of Standards and Technology, Boulder, Colorado 80305, USA
Implementing optical-frequency combs with integrated photonics will enable wider use of precision timing signals. Here, we explore the generation of an octave-span, Kerr-microresonator frequency comb using hybrid integration of an InP distributed-feedback laser and a SiN photonic-integrated circuit. We demonstrate electrically pumped and fiber-packaged prototype systems, enabled by self-injection locking. This direct integration of a laser and a microresonator circuit without previously used intervening elements, such as optical modulators and isolators, necessitates understanding self-injection-locking dynamics with octave-span Kerr solitons. In particular, system architectures must adjust to the strong coupling of microresonator backscattering and laser-microresonator frequency detuning that we uncover here. Our work illustrates critical considerations toward realizing a self-referenced frequency comb with integrated photonics.
