Coherent frequency transfer with < 5*10−21 stability via a multi-branch comb with noise cancellation

Abstract

We demonstrate a multi-branch frequency comb for spectral purity transfer incorporating hardware enabled noise cancellation based on a cw noise transfer laser. We verify coherent frequency transfer at stabilities ≈ 2×10−18 in 1 second and < 5×10−21 in 10,000 seconds without any reference cavity.