Embedding of end-tapered, thin-cladding silica fiber bundles for board-level high-repetition rate optical clock distributions is proposed. Fan-outs of 1-64- and 128-nodes on a printed circuit board of area 13 x 19 cm(2) are demonstrated. Dispersion measurement shows a 30-ps pulse broadening over 30-cm length of the fiber. Power coupling efficiency of 3 dB with coupling nonuniformity of 4.7-5.5 dB Is demonstrated.