BASED ON MCM TECHNOLOGY FOR WDM - Biblio

CARD･SIZE 10 Gbit/S OPTICAL TX/RX MODULES
BASED ON MCM TECHNOLOGY FOR WD'M
INTERCONNECTIONS IN Tbitls ATM SWITCHES
Naoki Takaya, Naoaki Yamanaka
NTT Network Service Systems Laboratories
3-9- 1 1 Midori-cho, Musashino-shi, Tokyo, 1 80-85 85 JAPAN
(Takava.Naoki@耶1ab.ntt.co.jr)) l
Phone: +81422-59-2154, Fax: +811422-59A549
Abstract : Ckrd-sized 10 GbiL/s optical h･ansmiHer r乃フand receiver rRりmoddes in a wavelength-division-
multipkdng r粁DM) Optical interconnection qsiem have been developed for nw-generation Tbids A TM switches.
TX and RXmoddes wereゐveloped using multi-chl'p modde iechnology･ me TXmodue has a 16:1 mulllblexer, and
the RXmodulehas a lJ16 dbmuliiblexer; both are 90X 50 X 15 mm, qprw'mately the size ofa credit card and onethird the size of conventional modues･ This WDM inlerconneciion based on cayd-size TX and RX mpdde will
advance the development of economical and practical乃iLrs A m switching SyStemS･
Switching size is expanded N times to achieve Tb/S
Introduction
switching,the number of TXand RX modules needed is
A s山一Tb/s ATM swit血ing system based on waveleng也division-multiplexing (WDM)叩tical interconnections has
been proposed for achieving large-capacity ATM networks
proportionalto N. Thus, small, low-power rnodules are
required.
Moreover, if也en WDM optical interconnection uses血ree
[1 】. Because large-capacity switching systems need many
high-Speed signalintercormections, fast and cornpact
interconnection inter血ces are needed in ATM switching
systems･ We previously proposed a WDM interconnection
system for interconnectlng electronicalunit switcheswith
different opticalwavelengths l1 ,3]･
However, to achieve a practicaトsized Tb/s ATM switching
system, the total size of the optical interconnection
interfaces must be scaled down drastically. Inthis paper,
we propose credit-card-sized 1 0-Gb/s optical transmitter
(TX) and receiver (RX) modules. Theyare fabricated using
downsizin.gand high-speedmiti-chip-module (MCM)
opticalAWGs (multiplexer, router and demultiplexer), we
must designthe system considering thatthe maximum loss
in optical power is possibly 20 dB. Therefわre,血e TX
modules should have high opticalpower, andthe RX
modules should have highopticalsensitivity･
Card-size 10 Chit/S optical TX and RX modules
A block diagram of the TX module is shown in Fig. 2(a)･ It
consists of three components: a TX IC (multiplexerand
clock generation), an electron-absorption (EA)/DFB laser,
andanEA driver･ The input interface consist of 622 Mb/s x
technologies. Performance evaluation showed that they are
16 data (Emitter Coupled Logic: ECL)and a differential
suitable fTor a practical WDM interconnection for Tb/s
622 MbJs clock (ECL). The multiplexer and clock-
ATM switching systems.
generation IC receivesthe 6221Mb/s x 16 ATM-cell data
and converts it into 10-Gb/s ATM-cell data. The clock is
WDM optical interconnections for Tbit/s ATM switches
generated using a VCO (Voltage Controlled Oscillator), a
A schematic diagram of our OPTIMA sub-Tb/S (640-Gb/S)
phase locked loop (PLL) circuit inthe TX IC,and an
ATM switching system is shownin Fig.1 l1]. It consists of
an 80-Gb/S ATM switch, anarrayed-waveguide (AWG)
router, eight 10-Gb/s transmitters, and eight 10-Gb/s
externalloop filter･ Power consumptlOn is 6.8 W, 30% less
thanwithexisting modules l3].
A block diagram of the RX module is shown in Fig.2 (ち). It
receivers･ The totalchannelthroughput per ATMunit
consists of two major COmPOnentS, PIN-PDand a receiver
switch is 80 Gb/S.
MCM･ The input interfTace is a 10-Gb/s optical signal, and
the output interface consists of 622 Mb/s x 16 data (ECL)
and differential 622-Mb/s clock (ECL). A trams-impedance-
Figure 1 : Schematic diagram of OPTIMA 640Gbit/s
ATM switching system.
type preamplifier is packaged into the PIN-PD. This
module is very compactand canachieve 52-dB gam at 8
GHz･ Power consumption is 6･2 W, approximately one-
fTourththat of convemional modules l3].
Using MCM technology reduced血e size to less than one-
third that of existing modules l2,3]. The MCM technique
we
used
to
integrate the
LSIs
is
effective
for
its
compactnessand low cost･ Figure 3 shows (a) an external
viewand (ち) the output wave form.s of the receiver MCM
(RX MCM). The RX MCM consists Of血ree GaAs ICs
(post-amplifier IC, limiting-amplifier IC,and 1:16
demultiplexer and clock/data recovery lC). ¶le Outer
▼
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dimension is 23.0 x 23.￠X 2.3 帆, with 84 Outer leads.
Each ICs are mounted oh a stage mode of CuW bimetal
To achieve 640-Gb/s switchingthroughput, 128 sets of TX
bo也to achieve血e high-speed operation and to improve
and RX modules are needed. Furthemore, if the total
the efficiency of heat radiation. The post-amplifier IC
ⅠⅠ -234
ECOC'99, 26-30 September 1999, Nice, France
amplifies the input slgnallinearlyand achieves a 16JB
毒＼>量
gain at 8 GHz･ The limltlng-amplifier IC achieves an 80
mvp-p output signalat 10 Gb/S･ The 1:16 dernultiplexer
and clock/data recovery IC receivesthe 10-Gb/s ATM-cell
data slgnaland converts it into sixteen 622-Mb/s ATM-cell
data slgnals･ The dataand differentialclock are regenerated
Figure 5 : 10 Gbit/s optical output wavefbrm･
by using it in a PLL circuitwithanextemalloop filter･ The
skews of allthe outputs are lessthan 50 ps･
ご飯も軌
The TXand RX modules are 90 X 50 x 15 mm each･ Figure
4 shows extemal views ofbo血modules.
Figure 6 : Bit error rate dlaraCteristics
Figtlre 2 : Block diagram of 10 Gbit/s TX and RX
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modules.
ConclusioJI
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Y we have developed card-size 10-Gb/s opticalTXand RX
modules by using MCM technology lT-rder to achieve a
Figure 3 : Extemal view of 10 Gbit/s RX MCM and
Tb/s ATM switching systems･ Measurements showedthat
otltPut WaVeforns･
these modules can operate stably and meet the
interconnections for large-capacity ATM switching
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requirements for practicalsystems, like WDM optical
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Figure 4 ･･ External views of card-si2:e lOGbit/s TX and
RX nodtLles.
systems･ Furthermore,the developed modules canbe
applied not only to WDM interconnection system butalso
to many kinds of systems like OC-192 transmission in
future broadband networks.
Ackn owiedg ments
we thank Mr. Atsunobu Ohta, Mr. Yoshikazu Ishii, Mr･
Niels C. Finsethand Dr. ToruTakada for supporting Our
work.
References
/1/ N. Yamanaka, S. Yasukawa, E. Oki,and T･ Kurimot0
--OPTIMA: Tb/S ATM Switching System Architecmre,
Based
on
Highly
Statical Optical
WDM
Interconnection,■● Proc･ IEEE ISS-97, pp･ 255-269,
1997.
/2/ M. Ushirozawa, K. Takahashi, M. Ishizaka, M･
Tachigori, T. Chuzenji, A. Noda,and. S･ Fujita.ISmal1sized 1 OG佃s Transmitterand ReceiverwithModulator
P erfo rman ce
The o叫ut WaVefbm of血e TX module is shown in Fig･ 5･
lt has a clear eye openlng, Showingthat average optical
output power was betterthan5dBm･ We measuredthe
opticalreceiver･S sensitivityto confirm its applicability to
1 OIGb/s lightwave transceivers･ Theminimum sensitivity
was -17.8 dBm at all error rate Of 10-llwith 223- I PRBS
lntegrated DFB-LD and Multichip-Module,-■ Proc･
ECOC96, 3, pp･ 195-198, 1996･
/3/ S. Yasukawa, N. Yamanaka, R･ Kawano, H･ Takeuchi,
and S. Kuwan0 -●Tb/s WDM Interconnection System
withPocket_Size lOG化s TranSmitte〟Receiver Module
and AWG Router;'Proc. ECOC'98, pp. 575-576, 1998･
(Fig. 6). These results showthat our proposed TX md RX
modules are applicable to WDM intercormections for Tb/s
ATM switching system
ECOC'99, 26-30 September 1999, Nice, France
ⅠⅠ -235

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