978-1-4673-7732-4/15/$31.00 ©2015 IEEE
Simultaneous All-optical WDM Multicast and
Unicast Scheme for WDM Optical Access Network
Based on SOA and AWG
Ze Li, Min Zhang*, Danshi Wang, Yue Cui
State Key Laboratory of Information Photonics and Optical Communications,
Beijing University of Posts and Telecommunications, Beijing 100876, China
E-mail: mzhang@bupt.edu.cn
Abstract²A simultaneous all-optical WDM multicast and
unicast scheme with large bandwidth for WDM optical access
network by using a multicast module based on FWM in SOA has
been proposed and verified. Two strategies of setting the
multicast module have been discussed to apply this scheme to
passive optical network and active optical network. One-to-four
WDM multicasts of 10Gb/s NRZ-OOK signal are successfully
obtained through FWM with two pumps in SOA, and all the four
multicast signals achieve error-free performance with power
penalty less than 4.3 dBm under BTB condition and over 20 km
fiber transmission in both strategies. This scheme is suitable for
processing the multicast services with sudden burst characteristic
and real-time demand to support with high speed, fast service
provisioning and high resource efficiency and may also play a
role of physical backup in case of the big data migration or the
network disaster.
Keywords²Multicast; optical access network; wavelength
division multiplexed; four-wave mixing; semiconductor optical
amplifier
I. INTRODUCTION
With the rapid development of cloud computing, mobile
Internet and electronic commerce, the exponential growth of
high-speed Internet traffic become an enormous challenge in
optical transport networks. To cope with traffic surge, building
more flexible and intelligent optical networks with ultra-high
bandwidth is envisaged as a promising solution to fulfill the
diverse bandwidth requirements for the emerging
heterogeneous network applications [1]. And thus new
technologies such as software defined optical network,
wavelength agile access network and space division
multiplexing (SDM) become the research hotspots in optical
network and transmission [2], [3], [4]. Among them, all-optical
wavelength division multiplexing (WDM) multicast, which can
efficiently replicate information from one input wavelength to
multiple output wavelengths, has been regarded as an
important and essential function in next generation all optical
networks, especially for several emerging services such as
ultra-high-definition TV, big data sharing, data center
migration, etc.[5], [6].
WDM optical access network (WDM-OAN), which
provide a separate wavelength channel and imply high access
bit rate between the optical line terminal (OLT) and each
optical network unit (ONU), is considered as one of the most
promising approaches to the future OAN [7]. The OAN of
typical point-to-multipoint architecture can be divided into
passive optical network (PON) and active optical networks
(AON) depending on using passive or active devices in optical
distribution network (ODN) and their common structure is
shown in Fig. 1 (a) [8]. Multicast function is crucial to
WDM-OAN to meet the exponentially increasing demand of
applications, such as IPTV and multimedia multicast. Several
multicast schemes for WDM-OAN have been proposed [9],
[10], [11], which implement the multicast function actually in
electronic domain and thus unavoidably limited in power
consumption and cost growth. In conventional WDM-OAN,
the OLT need to modulate the same data stream to some
certain wavelength channels and then transmit to the
corresponding ONUs to achieve WDM multicast as shown in
Fig. 1 (b), which is actually multicast in electronic domain.
However, for certain multicast services with high speed,
sudden burst characteristic and real-time demand (e.g., remote
group telemedicine, high definition live program, remote
real-time group traffic monitoring), all-optical WDM multicast,
which multicast directly in optical domain, can better achieve
WDM multicast in WDM-OAN with high speed, real time, fast
service provisioning and high resource efficiency. The
all-optical WDM multicast function occurring in the OLT or
remote node (RN) are illustrated in Fig.1 (c) and (d).
Meanwhile, to the best of our knowledge, all-optical WDM
multicast scheme in WDM-OAN has never been reported and
discussed its value and scenarios of application in access
network.
In this paper, we propose a simultaneous all-optical WDM
multicast and unicast scheme for NRZ-OOK signal with large
bandwidth in WDM-OAN, which can not only initiate the
multicast function depending on demand, but also play a role
of physical backup in case of the big data migration or the
network disaster. Through a multicast module (MM) based on
four-wave mixing (FWM) in semiconductor optical amplifier
(SOA), it is flexible to select the downlink wavelength for
multicasting and multicast to multiple wavelengths. It is elastic
to set the MM in the OLT or RN to adapt to the construction of
passive or active optical networks. The proposed scheme with
both strategies of MM settings is verified via VPI Transmission
Maker simulation platform and error-free performance of 10
Gb/s one-to-four NRZ-OOK WDM multicast signals is
achieved under back to back (BTB) condition and over 20 km