  We demonstrated transferring the stability of one highly stable clock laser
operating at 729 nm to another less stable laser operating at 698 nm. The two
different wavelengths were bridged using an optical frequency comb. The
improved stability of the clock laser at 698 nm enabled us to evaluate the
systematic frequency shifts of the Sr optical lattice clock with shorter
averaging time. We determined the absolute frequency of the clock transition
1S0 - 3P0 in 87Sr to be 429 228 004 229 873.9 (1.4) Hz referenced to the SI
second on the geoid via International Atomic Time (TAI).
