Fabrication of an ultra-high quality MgF2 micro-resonator for a single soliton comb generation

Crystalline micro-resonators are attractive for a wide range of applications due to their extremely high quality (Q) factor. In this paper, we develop a semi-automatic method for fabricating ultra-high Q-factor MgF2 crystalline micro-resonators. By utilizing a force feedback sensor and corresponding control, we made a semi-automatic precision grind-and-polishing machine, and successfully fabricated trapezoid MgF2 resonators with diameter of 9.5 mm and a root mean square surface roughness of 0.26 nm. The maximum difference of peaks and valleys is about 1.5 nm. The Q-factor was characterized to be 9.24 x 10(9)at 1550 nm by the cavity ring-down spectroscopy. A single soliton optical frequency comb was generated by pumping the microcavity with 150mW optical power.

Automated summary

In this paper, a semi-automatic method is developed to fabricate ultra-high Q-factor MgF2 micro-resonators. Trapezoid MgF2 resonators are successfully fabricated with a diameter of 9.5 mm, root mean square surface roughness of 0.26 nm, and a maximum difference of peaks and valleys of 1.5 nm. The Q-factor is characterized to be 9.24 x 10(9) at 1550 nm, and a single soliton optical frequency comb is generated by pumping the microcavity with 150mW optical power.