A multi-branch, fiber-based frequency comb with millihertz-level relative linewidths using an intra-cavity electro-optic modulator.
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.
Nakajima
Yoshiaki
Y
University of Fukui, Fukui, Fukui-ken, Japan.
Inaba
Hajime
H
Hosaka
Kazumoto
K
Minoshima
Kaoru
K
Onae
Atsushi
A
Yasuda
Masami
M
Kohno
Takuya
T
Kawato
Sakae
S
Kobayashi
Takao
T
Katsuyama
Toshio
T
Hong
Feng-Lei
FL
D004581:Electronics / Q000295:instrumentation*; D004867:Equipment Design; D019544:Equipment Failure Analysis; D005336:Fiber Optic Technology / Q000295:instrumentation*; D005374:Filtration / Q000295:instrumentation*; D007834:Lasers; D008872:Microwaves; D055096:Optical Devices; D012031:Refractometry / Q000295:instrumentation*; D014159:Transducers