  We present a Nd:YAG ultra-stable laser system operating at 946 nm and
demonstrate a fractional frequency instability of $1.1\times10^{-16}$ 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analog components have been replaced by FPGA-based digital electronics.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 $4\times10^{-17}$ at 1 s to the laser at 946 nm.
