including the management and installation costs by using wavelength independent optical network termination
(ONT). Spectrum-slicing using a broadband incoherent light source such as a light emitting diode (LED) may be
used to realize the wavelength independent ONT [1-3]. The LED can be fabricated at a low cost and modulated
directly. However, its output power and modulation speed are insufficient for high speed operation. The spectrum
sliced amplified spontaneous emission (ASE) based on EDFA had been proposed as a WDM source . However,
an expensive external modulator is required for transmission of signal. Recently, a wavelength locked Fabry-Perot
laser diode (F-P LD) with external spectrum-spliced amplified spontaneous emission (ASE) injection was proposed
as a low cost WDM source for wavelength independent operation of the ONT . By injecting spectrum-sliced
broadband light source (BLS) into a F-P LD, the laser is forced to operate in a quasi single mode and the mode
partition noise of the F-P LD is suppressed sufficiently to use as a WDM source.
We show optical access network configuration for FTTH based on WDM-PON in Fig. 1. Well known
internet protocol (IP) is used as a communication protocol between the central office and each home. Then
converged voice, data, and video services can be provided to each home with help of Ethernet switches and routers.
At customer’s home, the electrical switch classifies (It may be home gateway.) the traffic based on services and
provides data to the corresponding terminal equipments such as a TV set, a phone, or PCs. At the central office, a
high capacity electrical switch/router classifies the traffic based on service. Then, classified data were sent to metro
core networks. The core of this network is a WDM-PON that connects each subscriber to the central office. Then,
each subscriber communicates with the central office through dedicated wavelengths. A single wavelength channel
carries 4B5B coded 125 Mb/s Ethernet data to provide 100 Mb/s data to each home. Recently, we have
demonstrated feasibility of 50 GHz spaced WDM-PON based on wavelength locked FP-LD. Details of the WDM-
PON will be discussed at the conference.
Before deployment of the FTTH massively, the access network based on copper cable can be upgraded
with many kinds of PONs. A xDSL modem at subscriber’s home brings many operation and management issues,
since their fault rate is relatively high and it is not easy to access subscriber’s home. In addition, we have to use
optical fiber to extend services area of xDSL. At the termination point of the optical signal, we need a broad band
cabinet or a small hut that aggregates incoming traffic from subscribers and optical to electrical signal conversion,
or vice versa. It is not easy to find out the land to install the broad band cabinet. These problems can be solved by
using a pole mountable small size cabinet that includes a Fast Ethernet Switch (FES) or a L2 Ethernet switch with
an optical transceiver. Then, a PC located at subscriber’s home was connected to the FES through an unshielded
twisted pair (UTP) cable without the modem. The ONUs mounted on the pole were connected to the central office
by using the PON, such as the TDM-PON or the WDM-PON. Fig. 2 shows architecture for FTTPole system based
on the WDM-PON. In case of the TDM-PON, we need a media access protocol to share many ONUs in time
In conclusion, we investigated application of passive optical networks, especially WDM-PON, for FTTH
and FTTPole. The WDM-PON was realized based on wavelength locked FP-LDs for a low cost and wavelength
independent operation of ONT/ONU.
 M. Zirngibl, C. R. Doerr, and L. W. Stulz, “Study of spectral slicing for local access applications,” IEEE Photon. Technol. Lett., vol. 8, no. 5,
pp. 721-723, 1996.
 D. K. Jung, S. K. Shin, C. -H. Lee, and Y. C. Chung, “Wavelength-division- multiplexed passive optical network based on spectrum-slicing
techniques,” ” IEEE Photon. Technol. Lett., vol. 10, no. 9, pp. 1334-1336, 1996.
 R. D. Feldman, E. E. Harstead, S. Jiang, T. H. Wood, M. Zirngibl, “An evaluation of architectures incorporating wavelength division
multiplexing for broad-band fiber access,” IEEE J. Lightwave Technol., vol. 16, no. 9, pp. 1546-1559, 1998.
 H. D. Kim, S. -G. Kang, and C. –H. Lee, “A low cost WDM source with an ASE injected Fabry-Perot semiconductor laser,” IEEE Photon.
Technol. Lett., vol. 12, no. 8, pp. 1067-1069, 2000.
Services Bandwidth (down) Bandwidth (up)
Streaming Video (HD) Total 60 Mb/s
Live TV 20 M/service
VoD 20 M/service
EoD/GoD 20 M/service 20 M/service
Internet 10 Mb/s 10 Mb/s (P-to-P)
Video conference 2 ~ 20 Mb/s 2 ~ 20 Mb/s
Remote sensing/control 1 Mb/s 1 Mb/s
Total Bandwidth 73 ~ 91 Mb/s 33 ~ 53 Mb/s
Table 1. Various services and required bandwidth
OLT RN ONTs
OLT Switch BLS
TRx 1 Switch
TRx 1 PCs
A-BLS B-BLS Home 1
Metro Coupling optics
TRx 32 Switch
Fig. 1 A FTTH configuration based on WDM-PON
OLT RN ONU
TRx 16 (L2)
Fig. 2 A FTTPole configuration based on WDM-PON. The OUN was mounted on the pole.