We have created a broad spectrum spanning more than an optical octave by la
unching femtosecond pulses from a battery operated Cr:LiSAF laser into a ph
otonic crystal fiber. Despite the massive broadening in the fiber, the comb
structure of the spectrum is preserved, and this frequency comb is perfect
ly suited for applications in optical frequency metrology. (C) 2001 Optical
Society of America.