Gallium phosphide microresonator frequency combs

Abstract

We demonstrate the first microresonator frequency combs in GaP, a III-V semiconductor transparent above 549 nm. High Kerr nonlinearity (> 10<sup>-18</sup> m<sup>2</sup>/W) yields a 10-mW parametric threshold and 100-nm-wide combs with THz spacing, centered at 1550 nm.