Nakajima Yoshiaki, Inaba Hajime, Hosaka Kazumoto, Minoshima Kaoru, Onae Atsushi, Yasuda Masami, Kohno Takuya, Kawato Sakae, Kobayashi Takao, Katsuyama Toshio, Hong Feng-Lei
University of Fukui, Fukui, Fukui-ken, Japan.
Opt Express. 2010 Jan 18;18(2):1667-76. doi: 10.1364/OE.18.001667.
We demonstrate that fiber-based frequency combs with multi-branch configurations can transfer both linewidth and frequency stability to another wavelength at the millihertz level. An intra-cavity electro-optic modulator is employed to obtain a broad servo bandwidth for repetition rate control. We investigate the relative linewidths between two combs using a stable continuous-wave laser as a common reference to stabilize the repetition rate frequencies in both combs. The achieved energy concentration to the carrier of the out-of-loop beat between the two combs was 99% and 30% at a bandwidth of 1 kHz and 7.6 mHz, respectively. The frequency instability of the comb was 3.7x10(-16) for a 1 s averaging time, improving to 5-8x10(-19) for 10000 s. We show that the frequency noise in the out-of-loop beat originates mainly from phase noise in branched optical fibers.
我们证明，具有多分支配置的基于光纤的频率梳可以将线宽和频率稳定性在毫赫兹水平上转移到另一个波长。采用腔内电光调制器来获得用于重复频率控制的宽伺服带宽。我们使用稳定的连续波激光器作为共同参考来稳定两个频率梳中的重复频率，研究两个频率梳之间的相对线宽。在1 kHz带宽和7.6 mHz带宽下，两个频率梳之间的环路外拍频载波的能量集中度分别达到了99%和30%。对于1秒的平均时间，频率梳的频率不稳定性为3.7×10⁻¹⁶，对于10000秒则提高到5 - 8×10⁻¹⁹。我们表明，环路外拍频中的频率噪声主要源于分支光纤中的相位噪声。
