An Er:Fiber Femtosecond Optical Frequency Comb for Measurement of the D1 Line in Cold 6Li Atoms

In this paper, we demonstrate a home-made Er:fiber femtosecond optical frequency comb system. The system includes Femtosecond laser, detection and control of f
rep
and f
ceo
, Spectral broaden and Beat unit. By controlling the intra-cavity electro-optic modulator and piezoactuator, the f
rep
is stabilized with high bandwidth and large range (about megahertz bandwidth and 3 kilohertz range). In-loop frequency instability of f
ceo
and f
rep
are 3.7×10
^−
18
/τ
^1/2
and 1.8×10
^−
13
/τ
^1/2
respectively. By using highly nonlinear fiber and MgO: Periodically poled lithium niobate, the Spectral range of femtosecond optical frequency comb is extended from infrared 1520–1607 nm to 671 nm. This system can be commendably used in measurement of the absolute frequency of D
1
line in cold
⁶
Li atoms.