Long-haul dual-channel bidirectional chaos communication based
on polarization-resolved chaos synchronization between twin
1550 nM VCSELs subject to variable-polarization optical injection
Ling Wang
a
, Zheng-Mao Wu
a,
n
, Jia-Gui Wu
a
, Guang-Qiong Xia
a,b,
n
a
School of Physics, Southwest University, Chongqing 400715, China
b
State Key Lab of Millimeter Waves, Southeast University, Nanjing 210096, China
article info
Article history:
Received 24 May 2014
Received in revised form
19 July 2014
Accepted 18 August 2014
Available online 1 September 2014
Keywords:
Vertical-cavity surface-emitting lasers
(VCSELs)
Polarization-resolved chaos
synchronization
Chaos communication
Polarization division multiplexing
abstract
Based on the polarization-resolved chaos synchronization between twin 1550 nm vertical-cavity
surface-emitting lasers (VCSELs), a novel long-haul dual-channel bidirectional chaos communication
system is proposed. In this system, a time delay signature (TDS)-suppressed chaotic signal, generated by
a driving VCSEL (D-VCSEL) under double external cavity feedbacks (DECFs), simultaneously injects into
twin VCSELs by variable-polarization optical injection (VPOI) to synchronize them and enhance the
chaos output bandwidth of the two VCSELs. The simulated results show that, under proper injection
parameters, high-quality polarization-resolved chaos synchronization between the twin VCSELs can be
achieved; meanwhile the bandwidths of chaotic signals output from the twin VCSELs have been
enhanced in comparison with that of the driven chaotic signal. Based on the high-quality polarization-
resolved chaos synchronization, after adopting polarization-division-multiplexing (PDM) and chaos
masking (CM) techniques, four 10 Gb/s messages hidden respectively in four chaotic carriers can be
decrypted effectively after propagating 15 km in single-mode fi ber (SMF) links. After adopting
dispersion-shifted fibers (DSFs) as fiber links, the dual-channel bidirectional chaos communication
distance can be extended to 140 km.
& 2014 Elsevier B.V. All rights reserved.
1. Introduction
Chaos synchronization, firstly proposed by Pecora and Carroll
in 1990 [1], has attracted extensive attentions for its potential
application in information secure field at a physical layer. During
the last decades, enormous research efforts have been devoted to
chaos synchronization and communication based on semiconduc-
tor lasers (SLs) [2–18] owing to their broadband, high-speed and
compatibility with existing fiber optical networks. Previous works
concentrated mostly on the unidirectional chaos communication.
In 2005, Argyriset al. demonstrated 1 Gb/s message unidirectional
chaos-based communication in a 120-km commercial fiber-optical
network [8]. Later, in 2010, Lavrovet al. reported that 10 Gb/s
message was unidirectionally transmitted over more than 100 km
in fiber-optical network [9]. However, for the convenience of
information interactive transmission, bidirectional chaos commu-
nication is always highly expected.
Recently, many configurations have been proposed to realize
bidirectional chaos communication [10–17]. These configurations
can be mainly categorized into two classes: one is based on
the chaos synchronization between two mutually coupled SLs
(MC-SLs) [10–13], and the other is on the basis of chaos synchro-
nization between two SLs driven simultaneously by a common
chaotic signal [14–17]. Based on the latter, Wu et al. experimen-
tally demonstrated the chaos synchronization between twin DFB-
SLs separated by 40-km single-mode fiber (SMF) links in 2011 [16]
and two 2.5 Gb/s messages bidirectional transmission over 10-km
SMF channel with bit-error-rates estimated below 10
4
in 2013
[17]. In the above-mentioned bidirectional chaos communication
experiment systems, the SLs usually used are edge-emitting lasers
(EELs). Compared with EELs, vertical-cavity surface-emitting lasers
(VCSELs) exhibit many advantages such as single longitudinal-
mode operation, low threshold current, circular output beam with
narrow divergence, low cost and easy large-scale integration
into two-dimensional arrays. Especially, the outputs of VCSELs
generally include two orthogonal polarization components (i. e.,x
polarization component (x-PC) and y polarization component
(y-PC)) due to weak material and cavity anisotropies [18–21],
which can be exploited to create some novel applications. For
instance, through utilizing respectively x-PC and y-PC as two
Contents lists available at ScienceDirect
journal homepage: www.elsevier.com/locate/optcom
Optics Communications
http://dx.doi.org/10.1016/j.optcom.2014.08.041
0030-4018/& 2014 Elsevier B.V. All rights reserved.
n
Corresponding authors at: School of Physics, Southwest University, Chongqing
400715, China.
E-mail addresses: zmwu@swu.edu.cn (Z.-M. Wu), gqxia@swu.edu.cn (G.-Q. Xia).
Optics Communications 334 (2015) 214–221