Abstract: The inflationary scenario generically predicts the existence of primordial gravitational waves, which would leave an unique degree-scale B-mode polarization pattern in the Cosmic Microwave Background. The BICEP/Keck (BK) experiment is a series of telescopes located at the Amundsen Scott South Pole Station designed to measure this signature.

BICEP3, the latest instrument in the BK program, started its science observations in March 2016. It is a 550-mm-aperture refractive telescope observing the polarization of the Cosmic Microwave Background at 95 GHz. I will give an overview of the design and current status of the telescope, including various instrument and systematic performances. I will also talk about the BICEP Array, comprising four BICEP3-like receivers observing from 30 to 270 GHz, which is expected to replace the Keck Array starting in 2019.