TY - JOUR AU - Scott Diddams AU - D. Jones AU - Jun Ye AU - Steven Cundiff AU - John Hall AU - J. Ranka AU - R. Windeler AU - Ronald Holzwarth AU - Thomas Udem AU - T. Hänsch AB - We demonstrate a great simplification in the long-standing problem of measuring optical frequencies in terms of the cesium primary standard. An air-silica microstructure optical fiber broadens the frequency comb of a femtosecond laser to span the optical octave from 1064 to 532 nm, enabling us to measure the 282 THz frequency of an iodine-stabilized Nd:YAG laser directly in terms of the microwave frequency that controls the comb spacing. Additional measurements of established optical frequencies at 633 and 778 nm using the same femtosecond comb confirm the accepted uncertainties for these standards. BT - Physical Review Letters DA - 2000-05 DO - 10.1103/PhysRevLett.84.5102 N2 - We demonstrate a great simplification in the long-standing problem of measuring optical frequencies in terms of the cesium primary standard. An air-silica microstructure optical fiber broadens the frequency comb of a femtosecond laser to span the optical octave from 1064 to 532 nm, enabling us to measure the 282 THz frequency of an iodine-stabilized Nd:YAG laser directly in terms of the microwave frequency that controls the comb spacing. Additional measurements of established optical frequencies at 633 and 778 nm using the same femtosecond comb confirm the accepted uncertainties for these standards. PY - 2000 SP - 5102 EP - 5105 T2 - Physical Review Letters TI - Direct Link between Microwave and Optical Frequencies with a 300 THz Femtosecond Laser Comb VL - 84 SN - 0031-9007 ER -