  We demonstrate a self-referenced fiber frequency comb that can operate
outside the well-controlled optical laboratory. The frequency comb has residual
optical linewidths of < 1 Hz, sub-radian residual optical phase noise, and
residual pulse-to-pulse timing jitter of 2.4 - 5 fs, when locked to an optical
reference. This fully phase-locked frequency comb has been successfully
operated in a moving vehicle with 0.5 g peak accelerations and on a shaker
table with a sustained 0.5 g rms integrated acceleration, while retaining its
optical coherence and 5-fs-level timing jitter. This frequency comb should
enable metrological measurements outside the laboratory with the precision and
accuracy that are the hallmarks of comb-based systems. Work of the U.S.
government, not subject to copyright
