Title :
Frequency Uncertainty for Optically Referenced Femtosecond Laser Frequency Combs
Author :
Ma, Long-Sheng ; Bi, Zhiyi ; Bartels, Albrecht ; Kim, Kyoungsik ; Robertsson, Lennart ; Zucco, Massimo ; Windeler, Robert S. ; Wilpers, Guido ; Oates, Chris ; Hollberg, Leo ; Diddams, Scott A.
Author_Institution :
Bur. Int. des Poids et Mesures, Sevres
Abstract :
We present measurements and analysis of the currently known relative frequency uncertainty of femtosecond laser frequency combs (FLFCs) based on Kerr-lens mode-locked Ti:sapphire lasers. Broadband frequency combs generated directly from the laser oscillator, as well as octave-spanning combs generated with nonlinear optical fiber are compared. The relative frequency uncertainty introduced by an optically referenced FLFC is measured for both its optical and microwave outputs. We find that the relative frequency uncertainty of the optical and microwave outputs of the FLFC can be as low as 8times10-20 and 1.7times10-18, with a confidence level of 95%, respectively. Photo-detection of the optical pulse train introduces a small amount of excess noise, which degrades the stability and subsequent relative frequency uncertainty limit of the microwave output to 2.6times10-17
Keywords :
frequency standards; high-speed optical techniques; laser mode locking; lenses; optical Kerr effect; sapphire; solid lasers; titanium; Al2O3:Ti; Kerr-lens mode-locking; Ti:sapphire lasers; broadband frequency combs; femtosecond laser frequency combs; frequency uncertainty; laser oscillator; microwave output; nonlinear optical fiber; octave spanning combs; optical output; optical reference; Current measurement; Fiber lasers; Fiber nonlinear optics; Frequency measurement; Laser mode locking; Masers; Nonlinear optics; Optical noise; Ultrafast optics; Uncertainty; Femtosecond laser; frequency comb; optical frequency metrology;
Journal_Title :
Quantum Electronics, IEEE Journal of
DOI :
10.1109/JQE.2006.886836
