High-repetition-rate pulsed fiber laser based on
virtually imaged phased array
Xuanjuan Chen (陈璇娟)
1
, Yuxin Gao (高玉欣)
2
, Jiamin Jiang (江嘉敏)
1
,
Meng Liu (刘 萌)
1,
*, Aiping Luo (罗爱平)
1
, Zhichao Luo (罗智超)
1
,
and Wencheng Xu (徐文成)
1,
**
1
Guangzhou Key Laboratory for Special Fiber Photonic Devices and Applications & Guangdong
Provincial Key Laboratory of Nanophotonic Functional Materials and Devices, South China Normal University,
Guangzhou 510006, China
2
Department of Mechanical and Electrical Engineering, Shandong Polytechnic College, Jining 272067, China
*Corresponding author: mliu@m.scun.edu.cn; **corresponding author: xuwch@scnu.ed u.cn
Received March 19, 2020; accepted April 16, 2020; posted online June 5, 2020
High-repetition-rate (HRR) pulsed fiber lasers have attracted much attention in various fields. To effectively
achieve HRR pulses in fiber lasers, dissipative four-wave-mixing mode-locking is a promising method. In this
work, we demonstrated an HRR pulsed fiber laser based on a virtually imaged phased array (VIPA), serving as a
comb filter. Due to the high spectral resolution and low polarization sensitivity features of VIPA, the 30 GHz
pulse with high quality and high stability could be obtained. In the experiments, both the single-waveband and
dual-waveband HRR pulses were achieved. Such an HRR pulsed fiber laser could have potential applications in
related fields, such as optical communications.
Keywords: dissipative four-wave-mixing; high-repetition-rate pulse; virtually imaged phased array.
doi: 10.3788/COL202018.071403.
As the sources of optical pulses in the picosecond and fem-
tosecond range, ultrafast fiber lasers play important roles
in the areas of optical communications, biomedicine, and
chemical detection
[1,2]
. During the developments of ultra-
fast fiber lasers, shorter pulse dura tion, higher pulse en-
ergy, and larger pulse repetition rate are the main goals for
industrial applications. Particularly, the high-repetiti on-
rate (HRR) pulsed fiber laser is the key component in
areas of high-capacity telecommunication systems and
microwave photonics
[3,4]
. Generally, the HRR pulse could
be achieved by cutting down the length of the laser
cavity
[5–7]
and high-order harmonic mode-locking
[8–14]
.
However, the former has a hard time achieving a pulse
train with a higher than 20 GHz repetition rate due to the
limited physical cavity length, while the latter is mainly
limited by the instability. Fortunately, it has been dem-
onstrated that dissipative four-wave-mixing (DFWM)
mode-locking could be employed to easily and effectively
generate HRR pulses with repetition rate of even up to
tens or hundreds of gigahertz (GHz)
[15–25]
. As we know,
the comb filter is one of the key devices to realize DFWM
mode-locking. The fineness of the comb filter greatly af-
fects the HRR pulse quality, and the free spectral range
(FSR) of the comb filter determines the pulse repetition
rate. So far, several types of comb filters have been utilized
in DFWM mode-locked lasers to obtain HRR pulses. In
2013, Mao et al. used a Mach–Zehnder interferometer with
variable FSR to obtain repetition-rate tunable HRR
pulses
[20]
. As the multi-wavelength selective components,
a Fabry–Perot comb filter was employed, and a 100 GHz
pulsed fiber laser was obtained
[22]
. Recently, the nonlinear
micro-cavity and graphene-deposited microfiber knot
resonator, that provide the highly nonlinear effect and
comb filtering effect at the same time, were demonstrated
to be effective for the HRR pulse generation by DFWM
mode-locking
[19,23]
. These successful experimental results
motivate us to continue searching for other kinds of comb
filters with good performance for DFWM mode-locking.
On the other hand, the virtually imaged phased array
(VIPA) is a “side-entrance” Fabry–Perot etalon-structure-
based optical spectral disperser
[26]
. It achieves high spectral
dispersion through the interference of multiple reflections
between two interfaces of a solid etalon. Therefore, the
VIPA also possesses the comb filtering effect. Due to its
advantages, including large angular dispersion, low depend-
ence of the input polarization state, and simple structure,
the VIPA plays important roles in various areas, i.e., wave-
length division multiplexing (WDM), dispersion compen-
sating, and spectroscopy
[26–30]
. Particularly, because of the
high spectral resolution feature of VIPA, it has been em-
ployed as the hyperfine wavelength demultiplexer
[26,28]
.
Xiao et al. demonstrated a multi-channel hyperfine wave-
length demultiplexer at 1550 nm with the VIPA, whose
channel spacing is 24 pm, and the 3 dB channel bandwidth
is 6 pm
[28]
. Then, some questions would naturally arise as
to whether the VIPA could act as the comb filter for the
DFWM mode-locking, and whether the high spectral reso-
lution and low polarization sensitivity features of VIPA
would be beneficial for the high-quality, high-stability
HRR pulse generation.
In this work, taking advantag e of the high spectral
resolution and low polarization sensitivity features of VIPA,
an HRR pulse with high quality and high stability was
achieved in an Er-doped fiber (EDF) laser. Here, the DFWM
COL 18(7), 071403(2020) CHINESE OPTICS LETTERS July 2020
1671-7694/2020/071403(4) 071403-1 © 2020 Chinese Optics Letters