Challenges Toward Practical WDM PON
Y. C. Chung
Korea Advanced Institute of Science and Technology
Department of Electrical Engineering
373-1 Guseong-dong, Yuseong-gu, Daejeon 305-701, Korea
(phone) +82-42-869-3456, (fax) +82-42-869-3410, (email) ychung@ee.kaist.ac.kr
Abstract
We review the current challenges in WDM PON for
the practical deployment and report the relevant
technical progresses achieved at KAIST.
1. Introduction
Recently, FTTH has finally emerged from the R&D
stage and became a commercial reality. For example,
in Japan, it has been reported that the total number of
FTTH subscribers exceeded 1.5 million in 2004. In
US, there have been numerous announcements of
FTTH deployments by both operating companies and
municipalities. It appears that this trend is rapidly
spreading all over the world. At present, most of the
FTTH deployments utilize TDM PON (such as
APON/ BPON, GPON, and EPON). However,
WDM PON is beginning to attract significant
attention,
as Korea
started
its
commercial
deployment this year. In fact, WDM PON has long
been considered as an ultimate solution for the access
networks due to its large capacity, easy management,
network security, and upgradeability. In this paper,
we review the current issues in WDM PON and
report the relevant technical progresses achieved at
KAIST.
2. Low-cost WDM Light Sources
Although WDM PON has many advantages, it has
been considered to be prohibitively expensive for the
practical deployment. This is mainly due to the extra
costs involved in the installation and maintenance of
the wavelength-selected lasers required in WDM
PON. To solve this problem, it has been proposed to
implement WDM PON by using the spectrum-sliced
incoherent light sources (such as LEDs or ASE
sources) or ASE- injected Fabry-Perot lasers [1]-[4].
The main advantage of such networks would be the
use of identical light source at every subscriber’s site.
We will review various network architectures using
thes