946-nm Nd:YAG digital-locked laser at 1.1 × 10-16 in 1 s and transfer-locked to a cryogenic silicon cavity.

We present a Nd:YAG ultra-stable laser system operating at 946 nm and demonstrate a fractional frequency instability of 1.1×10-16 at 1 s by pre-stabilizing it to a 30-cm-long ULE cavity at room temperature. All key analog components have been replaced by FPGA-based digital electronics. To reach an instability below the 10-16 level, we transfer the stability of a 1542 nm laser stabilized to a cryogenic silicon cavity exhibiting a fractional frequency instability of 4×10-17at 1 s to the laser at 946 nm.