Open AccessA multi-branch, fiber-based frequency comb with millihertz-level relative linewidths using an intra-cavity electro-optic modulator
Author(s) -
Yoshiaki Nakajima,
Hajime Inaba,
Kazumoto Hosaka,
Kaoru Minoshima,
Atsushi Onae,
Masami Yasuda,
Takashi Kohno,
Sakae Kawato,
T. Kobayashi,
T. Katsuyama,
Feng−Lei Hong
Publication year - 2010
Publication title -
optics express
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.394
H-Index - 271
ISSN - 1094-4087
DOI - 10.1364/oe.18.001667
Subject(s) - optics , laser linewidth , frequency comb , beat (acoustics) , bandwidth (computing) , phase noise , materials science , wavelength , optical fiber , relative intensity noise , fiber laser , laser , physics , semiconductor laser theory , telecommunications , computer science
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.