Self-referenced photonic chip soliton Kerr frequency comb

• 来源期刊: 光：科学与应用（英文版）
• 关键词: frequency combs integrated optics Kerr frequency combs metrology microresonator frequency combs nonlinear optics
• 年，卷（期）: 2017,（1）
• 页码范围: 75-80
• 页数: 6页
• 语种: 英文
• DOI: 10.1038/lsa.2016.202

摘要

Self-referencing turns pulsed laser systems into self-referenced frequency combs.Such frequency combs allow counting of optical frequencies and have a wide range of applications.The required optical bandwidth to implement self-referencing is typically obtained via nonlinear broadening in optical fibers.Recent advances in the field of Kerr frequency combs have provided a path toward the development of compact frequency comb sources that provide broadband frequency combs, exhibit microwave repetition rates and are compatible with on-chip photonic integration.These devices have the potential to significantly expand the use of frequency combs.Yet to date, self-referencing of such Kerr frequency combs has only been attained by applying conventional,fiber-based broadening techniques.Here we demonstrate external broadening-free self-referencing of a Kerr frequency comb.An optical spectrum spanning two-thirds of an octave is directly synthesized from a continuous wave laser-driven silicon nitride microresonator using temporal dissipative Kerr soliton formation and soliton Cherenkov radiation.Using this coherent bandwidth and two continuous wave transfer lasers in a 2f-3f self-referencing scheme, we are able to detect the offset frequency of the soliton Kerr frequency comb.By stabilizing the repetition rate to a radio frequency reference, the self-referenced frequency comb is used to count and track the continuous wave pump laser's frequency.This work demonstrates the principal ability of soliton Kerr frequency combs to provide microwave-to-optical clockworks on a chip.