Low Power Consumption 10 Gbps×12 ch Parallel Optical Module
for Optical Interconnection
Yozo Ishikawa *, Atsushi Izawa *, Yoshinobu Nekado *, Masakazu Yoshiwara *,Katsutoshi Takahashi *, Toshinori Uemura *, and Hideyuki Nasu *Recently, with rapid increases in the data volume processed in data centers,
great expectations are placed on the introduction of optical interconnects witha transmission speed of higher than 10 Gbps per channel. Whereas optical interconnects showsuperior performance in terms of long-distance transmission, high-data rate transmission andlow power consumption, the advantage mentioned last is presently drawing special attention, as
the consciousness for the environment is on the rise among IT equipment manufacturers.
Furukawa Electric has been developing a compact 10 Gbps×12 ch parallel optical module thatis applicable to both inter-equipment and intra-equipment communications in data centers, andby using low-power consumption ICs and our high-efficiency 1 µm-range VCSEL that allows lowbias current driving, we have recently achieved a low power consumption of 7 mW/Gbps. This
paper presents the structure and characteristics of parallel optical modules.

ABSTRACTINTRODUCTION

With the rapid spread of the Internet, the data volume processed by servers and storages in data centers is rapidly
increasing. To improve the data processing volume,
efforts are being made to raise the speed of individual
devices. And on the other hand, the communication
speed in CPU-to-memory and device-to-device is needed
to be increased, thereby making it essential to upgrade
the speed of interconnections.
Heretofore, despite its high transmission loss, electricinterconnects have been used for its low cost and ease ofhandling in interconnections in data centers and the like,because the transmission distance needed is rather limited. Recently, however, the data volume to be processed
increases year by year, making it necessary to improvethe data capacity that can be processed by one interconnection. Accordingly, a data rate in excess of 10 Gbps isoften required these days even in intra-device communications, and this leads to the argument over the limits ofelectric interconnects, accompanied by active studies on
the introduction of optical interconnects.
Figure 1 shows the boundary between optical interconnection and electrical interconnection, using transmission
distance and signal speed as parameter 1). The boundary
shown in solid line indicates that, when a data rate
exceeding 10 Gbps is required, electrical interconnect is
expected to achieve a transmission distance of several
meters at most. On the other hand, optical wiring canachieve longer distance data transmission because it hasa significantly smaller transmission loss compared withthat of electrical wiring, and it is less susceptible to noisefrom exterior environments. Optical interconnects include
the parallel optical link using SNAP12 2) capable of 300 m
transmission by 2.72 Gbps×12 ch, and the optical link
standardized by IEEE 802.3ae 10 GBASE-SR (10 GbE) 3).
Hereafter, standardization of IEEE P802.3ba 40 Gbps and
100 Gbps Ethernet task force (100 GbE) is scheduled in
2010, holding promise for parallel optical links having adata rate higher than 10 Gbps×10 ch.

OpticalSignal speed（Gbps）

1.

10

Electrical
1

0.1

1

10

100

Transmission distance（m）

Figure 1

Boundary between optical interconnection and electrical interconnection, using transmission distanceand signal speed as parameter.

* FITEL Photonics Lab., R&D Div

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Low Power Consumption 10 Gbps×12 ch Parallel Optical Module for Optical Interconnection

2.

CONCEPT OF OPTICAL INTERCONNECTION MODULE

Optical interconnections can be classified, according to
the transmission distance, into rack-to-rack, board-toboard, chip-to-chip and in-chip categories, and the transmission distance of these categories falls into longer than
10 m, around 1 m, around 10 cm and shorter than 10 cm,
respectively. As the transmission distance decreases fromthe inter-rack to in-chip, components are required to be
mounted in higher density along with higher downsizing.
When it comes to optical module, parallel optical modules
with a total data rate of several tens of Gbps are commercially available, representatives of which are those basedon SNAP12 and active optical cable (AOC). Also, forboard-to-board transmission, the development of a compact parallel optical module with a data rate of higher than
10 Gbps per channel has been reported 6), 7).

connects is expected to reduce transmission losses, andto improve the cooling efficiency in equipment because it
can reduce the total amount of wiring thereby increasing
the space for free air convection. However, since speedup of information processing performance is ever accelerating presently, reduction of transmission loss andimprovement of cooling efficiency alone can not suppress
the increases in power consumption.
Figure 3 shows the trends in the power consumption
per 1 Gbps required for interconnections by 2020. As canbe seen, the power consumption is around 40 mW/Gbps
presently because electric interconnects constitute themainstream, but it is expected to reduce to 10 mW/Gbps
in 2012 due to employment of optical interconnects forboard-to-board transmission, then to 3 mW/Gbps in 2016
due to use of optical interconnects for chip-to-chip transmission, and finally to 1 mW/Gbps in 2020 due to use of
optical interconnects for in-chip transmission, thus showing a remarkable reduction in power consumption.
Power/Bandwidth（ｍW/Gb/s/link）

We have been developing a compact parallel opticalmodule that can achieve a transmission capacity of
10 Gbps×12 ch for a distance of up to several hundred
meters, being also applicable to high-density mounting,and a low-power consumption of 7 mW/Gbps has beenachieved under the working conditions that match actual
applications by using our high-efficiency 1 µm-range vertical cavity surface emitting laser (VCSEL) array 4), 5). This
paper presents the concept, structure and characteristicsof the developed module.

40 ｍW/Gb/s（Electrical I/〇） Board-to-board

10 mW/Gb/s（Optical）
1/5 per 4 years

2008

Rack-to-rack
Board-to-board

〜1ｍ
＞10ｍ

Figure 2

Schematic views of rack-to-rack and board-to-board
interconnection.

As information processing capability increases in recent
years, the power consumption in information processing
facilities tends to increase, and this constitutes a pending
problem. Also, the increase in power consumption due tothe speed-ups of devices, together with the increase in
the number of equipment, generates a concern.
Furthermore, it is said that air-conditioners in the existingdata centers consume more than 30% of the total electric
power. This constitutes a major problem, together with thepower consumption increases in air-conditioners to suppress temperature rises due to heat generation, and theone that is consumed to compensate for the decreased
cooling efficiency caused by high-density arrangement ofequipment. Introduction of optical technology into inter-

Figure 3

Low power
devices
VCSEL/PDLDD/TIA2012

Chip-to-chip

In chip

3 mW/Gb/s

1 mW/Gb/s

Ultra low power IC
Low power VCSEL
Ext. Mod. +VCSEL Silicon Photonics
Polymer waveguide （SiGe-PD, etc.）
Driver free

Year

2016

2020

Trends in power consumption of interconnections1), 8).

We have been developing a compact parallel opticalmodule with a data rate of 10 Gbps×12 ch, a power consumption of less than 10 mW/Gbps, that is applicable toboth rack-to-rack and board-to-board applications. To satisfy both a data rate of 120 Gbps and low power consumption, laser diode driver (LDD) and trans-impedance
amplifier (TIA) utilizing bipolar complimentary metal-oxidesemiconductor (BiCMOS) technology are employed. In
addition, a 1 µm-range indium-gallium-arsenide (InGaAs)
VCSEL array is used for the transmitting module, and an
InGaAs photo diode (PD) array having high responsivity
at the 1 µm-range for the receiving module.
Compared to 850 nm-range gallium-arsenide (GaAs)
VCSEL that is generally used for optical interconnections,the 1 µm-range VCSEL has higher differential gain 9), anda higher relaxation oscillation frequency is available using
the same threshold and drive currents, so high-speed
operation becomes possible 10). Because sufficient bandwidth is obtained with a lower drive current at the data
rate of 10 Gbps, it becomes possible to decrease power
consumption of optical modules.
In terms of transmission characteristics of optical links,
it becomes necessary to assure large power budget margin for transmission between the optical transmitting mod-

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Low Power Consumption 10 Gbps×12 ch Parallel Optical Module for Optical Interconnectionule (TX) and receiving module (RX). Table 1 compares thecharacteristic items determining the power budget margin
for transmission in the 1 μm-range and 850 nm-range.
Table 1

Items

Comparison of the characteristics of optical link components at 1050 nm and 850 nm.
Details

Rx-module, PD Responsivity
Opticalfiber
Tx-module,
Eye safety

1 µm-range（1050 nm）

850 nm-range（850 nm）

0.75 A/W

0.6 A/W

Transmission loss

0.95 dB/km

2.09 dB/km

Chromatic
dispersion－34.01ps/（nm·km）－90.42ps/（nm·km）

Maximum optical
output power+1.5 dBm
Class 1,
12 ch module－2.2 dBm
Class 1,
12 ch module

The InGaAs PD we use for the RX has a responsivity of
0.75 A/W at 1050 nm, which is larger than that of commonly used GaAs PD, i.e., 0.6 A/W. Given the fact that the
optical responsivity of RX is an important parameter constituting an optical link, the use of the 1 µm-range
achieves better optical responsivity by about 1 dB.
Silica-based multi-mode fiber (MMF) has wavelength
dependence in its transmission loss and chromatic dispersion. The transmission loss of the MMF used in thisdevelopment at the 1 µm-range is lower than that at the
850 nm-range by about 1 dB/km. Since the chromatic dispersion at the 1 µm-range is about one third of that of
850 nm-range, when comparison is made based on thesame wavelength width, signal waveform distortion canbe suppressed low even at longer transmission distances.
When a transmission distance exceeding several hundred
meters is needed, use of the 1 µm-range that is less sensitive to chromatic dispersion is more effective.
The maximum optical output of a TX is specified by theIEC under the eye safety regulations 11). In the case of
12-channel module using optical connection like MT connector, it is estimated that an optical output power that islarger by about 3 dB is available at the 1 µm-range inClass 1 specification. If the optical output of a TX can be
set high, it becomes possible to obtain higher power budget margin.
From the comparisons above, it can be said that the
1 µm-range is more effective in designing an optical linkthat offers a large power budget margin in terms of transmission distance.

3.

heat generated by the IC (LDD or TIA) is conducted to aheat sink to be dissipated via a metal cover provided
atop.

ｍ
m
13

13m

ｍ

Figure 4

Photo of parallel optical module 12).

When the optical module is mounted on a PCB, which
is a possible configuration envisioned in board-to-board
transmission, many other devices are also mounted on
the same PCB. If the optical module is directly mounted
using solder, it would be necessary to replace the whole
PCB in case of malfunction. We have developed, therefore, a pluggable socket as electrical interface 13) in orderto make module replacement easy. Figure 5 shows anexample of optical module mounted by using an electricalpluggable socket. The pluggable socket has a set ofspring pins two-dimensionally arrayed at 1 mm pitch, andthe high-speed I/O pin configuration has a wide-bandwidth of more than 10 GHz. The heat sink is used to press
the optical module against the socket, thereby electricallyconnecting the module and the PCB to effect signal transmission.

Heat sink
Optical module

Electrical pluggableinterface

PCB

STRUCTURE OF THE DEVELOPEDOPTICAL MODULE

Following the description in the preceding Section ofsome of the important concepts of parallel optical modules, the structure of the developed device will be presented in this Section. Figure 4 shows a photo of the optical module of pig-tail type. The mechanical size excluding3
the pig-tail are 13×13×3.4 mm , sufficiently compact for
high-density mounting, and an electrical interface adapt2
ed to the 11 mm footprint is provided on its bottom. The

MPO connector

Figure 5

Parallel optical module and electrical pluggable socket.

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Low Power Consumption 10 Gbps×12 ch Parallel Optical Module for Optical Interconnection

Optical eye
diagrams
Temperature
control unit

Pulse patterngenerator

TX Module

×12

Figure 6

4.

Electricalpluggable socket

Electricalpluggable socket

Evaluation board

Evaluation board

SPI

Characteristics of the optical module will be presented inthis Section. Figure 6 shows the evaluation system for the
optical module. The TX and RX optical modules are each
mounted onto the evaluation board via the electrical pluggable socket; a set of 12-channel broadband differential
transmission lines is provided on the board; they are connected with a pulse pattern generator (PPG), oscilloscopeand error detector, via RF cables equipped with compact,broadband connectors; and a temperature control unit isused to control the case temperature of the optical module. While changing the case temperature, measurements
were made of the optical output of TX, the electrical output waveform of RX in back-to-back (BTB) transmission
and the bit-error-rate (BER).
Figure 7 shows the output waveforms of the TX and RX
under 12-channel simultaneous operation at different temperatures from 15℃ to 80℃. The bias current of the VCSEL
in TX was set to 4 mA, while the extinction ratio was 4.5 dB
at 25℃. It can be seen that although the temperature risefrom 15℃ to 80℃ increases the waveform overshoot, goodeye opening is obtained. With the RX also, good performance was obtained including a differential amplitude of
240 mVpp, rise time/fall time of 35.7 ps/37.5 ps and goodeye opening at the full temperature range.
25℃

50℃

×12

Error
detector

suppressed by optimizing the optical output of TX, transmission distance and optical-fiber bandwidth, but in general, it is necessary to make an allowance of about 3 dB.
Thus in this study, the optical link has achieved a marginhigher than 2 dB.
80℃
50℃
25℃

10−4

15℃

10−6

10−8

10−10
10−12
-18

-16

-14

-12

-10

-8

Average received optical power（dBm）

Figure 8

BER characteristics at temperatures from 15°C to
14)
80°C .

80℃

TX
outputRX
outputFigure 7

SPI

DC 3.3V

Electrical eye
diagrams

Block diagram of test setup for optical module 14).

CHARACTERISTICS OF OPTICAL MODULE

15℃

RX Module

ATT

BER

10 Gbit/s NRZ
Mark ratio：1/2
PRBS：231−1

×12

Temperature
control unit

Output waveforms of TX-module and RX-module 14).

Figure 8 shows the BER characteristics in back-to-backtransmission. The minimum optical sensitivity at–12
BER=10 is seen to change from –11 dBm to –9.5 dBm
at different temperatures from 15℃ to 80℃. Given an optical output of TX of –4 dBm, the power budget margin of
the optical link is 5.5 dB. Transmission penalty can be

Figure 9 shows the relationship between the bias currentof the VCSEL in TX and the power consumption at 25℃
and 80℃. It can be seen that the power consumption of
TX is proportional to the bias current, and the proportionality coefficient is larger for the case temperature of 80℃.
The optical output waveform of selected 850 nm
VCSELs was evaluated at 25℃, and the results suggested
that higher than 5 mW/Gbps was expected for TX power
consumption because good eye-opening was obtained ata bias-current higher than 6 mA. In the case of the TX thatmounted 1 µm-range VCSEL, good optical-output wave–12
in BTB
form and error-free transmission with BER=10
were obtained at a bias-current of 4 mA. The TX power
consumption under this condition is about 3 mW/Gbps,
which is about 60% that of the TX employing a conventional 850 nm VCSEL.

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Low Power Consumption 10 Gbps×12 ch Parallel Optical Module for Optical Interconnection

8.0
7.0Power consumption（mW/Gbps）

5.1

25℃

850 nm VCSEL

80℃

6.0
5.0
1 µm-range
VCSEL

4.0
3.0
2.0
1.0
0.0

0

2

4

6

8

10

VCSEL bias current（mA）

Figure 9

Bias-current dependency of TX-module power con14)
sumption .

Figure 10 shows the relationship between the total
power consumption of TX plus RX and temperature from
15℃ to 80℃, indicating that the power consumption per
1 Gbps is 7 mW/Gbps. In extending transmission distances, the power consumption of TX may rise due to possible
increase of the extinction ratio of TX in consideration oftransmission penalty. However, in view of the fact that it
has a sufficient margin up to 10 mW/Gbps, it can be said
that this optical module adequately satisfy the power consumption estimated for 2012.

109Upper Limit of Transmission Distance of
1 µm-range Optical Link
Whereas the transmission distance in the rack-to-racktransmission at 10 Gbps/ch is said to be 300 m at most, it
is sometimes required to lengthen it to 300 m or longer.
The transmission distance is strongly affected by themode dispersion of MMF, and the effect is expressed by
the fiber bandwidth, so that MMFs for optical interconnects are standardized by an international regulation for
their bandwidth. The International ElectrotechnicalCommission (ISO/IEC) 11801 defines the fiber with theminimum bandwidth higher than 500 MHz·km at 850
nm/1300 nm as OM2, and the one with an effective minimum bandwidth higher than 2000 MHz·km at 850 nm as
OM3. The 10GbE specifies OM2 for transmission up to
82 m, and OM3 for up to 300 m, and for transmission
beyond 300 m, standardization of OM4 fiber with an effective minimum bandwidth of 4700 MHz·km is under study.
We prototyped an MMF whose bandwidth was optimized for 1050 nm in wavelength to construct a
1 µm-range optical link, and investigated the upper limit oftransmission distance of the optical link. The over-filled
launched (OFL) bandwidth of the fiber was 4300 MHz·km,
sufficiently wideband characteristics almost equivalent to
the effective bandwidth of OM4.
Figure 11 shows optical output waveforms after transmission over different distances. Although almost no
waveform degradation is seen from BTB up to 650 m, theinter-symbol interference (ISI) penalty begins to increase
from 800 m resulting in deterioration of eye opening.
Between the BTB and 1000 m, the extinction ratio deteriorates by nearly 2 dB, and at 1300 m the waveform deterioration reaches such a level that the rise time/fall time can
not be measured.

Power/Data rate（mW/Gbps）

8
7

BTB

300m

650m

800m

1000m

1300m

6
5
4
3
2
1
0
10

20

30

40

50

60

70

80

Case temperature（℃）

Figure 10 Case-temperature dependency of TX-module power
14)
consumption .

5.

TRANSMISSION CHARACTERISTICS
OF 1 µm-range OPTICAL LINK

Following the description of low-power operation of the
1 µm-range optical link in Section 4, this Section will present the transmission characteristics of optical links using
several kinds of optical fibers.

Figure 11 Optical eye diagram after transmission over different
distances.

Figure 12 shows the BER characteristics of the opticallink. Although an error floor is seen in the 1300 m transmission due to an S/N degradation due to ISI penalty,error-free transmission is achieved up to 1000 m with
–12
BER=10 , demonstrating an optical sensitivity lower
than –8 dBm. Given the fact that the upper transmission
limit of this optical link is defined to be more than 1000 m,
it has been demonstrated that the 1 µm-range optical link
is appropriate to applications up to 1 km.

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Low Power Consumption 10 Gbps×12 ch Parallel Optical Module for Optical Interconnection

Power penalty（dB）

BTB
300m
650m

10−4

800m

BER

1000m

1050 nm experiment1050 nm cal
850 nm cal

8
6
4
2
0

0

10−6

400

600

800

1000

Figure 13 Relationship between power penalty and transmission distance.

5.2

10−8

10−10
10−12
-18

200

Transmission distance（m）

1300m

-16

-14

-12

-10

-8

-6

-4

-2

Average received optical power（dBm）

Figure 12 BER characteristics after transmission over different
distances.

Figure 13 shows the relationship between transmission
distance and power penalty, which is defined as opticalsensitivity difference using BTB as a benchmark. The dots
indicate the actual measured data obtained from the BER
measurements mentioned before, while the solid lines
correspond to the evaluation results calculated using the
spread sheet disclosed by IEEE 15), obtained under theconditions of the center wavelength of 1050 nm, root
mean square (rms) wavelength width of 0.42 nm and the
OFL bandwidth of MMF of 4300 MHz·km. Power penalties
at 700 m and 1000 m in the estimation are 3 dB and morethan 9 dB, respectively, but the data show a power penalty of 3.2 dB at 1000 m, which is significantly lower thanestimation. This may be attributed to the fact that the
propagation condition within the MMF in the optical linkdiffers from OFL conditions, and the propagation modes
are limited resulting in an actual bandwidth that is larger
than the OFL condition. The dashed line shows the calculated results of the power penalty, when the center wavelength is set to 850 nm while other conditions are madethe same. Transmission distance at a power penalty of
3 dB is expected to be less than 500 m. On the other
hand, the transmission distance at 1050 nm in wavelengthis estimated to be 700 m, longer than the distance at
850 nm by 200 m, because the 1050 nm chromatic dispersion is smaller than that at 850 nm. Therefore, in thecase of transmission longer than 500 m employing awide-bandwidth MMF, a larger power budget margin is
expected than 850 nm, by using the 1 µm-range wavelength.

Transmission Characteristics of 1 µm-range
Optical Link Using Conventional MMF
Although silica-based MMFs used in optical interconnections are classified into OM2 and OM3 in terms of transmission bandwidth, these are targeted at usage in 850 nm
and 1300 nm. Since the 1 µm-range bandwidth for OM2
and OM3 is not standardized, their performance is notwidely known. The transmission characteristics of
1 µm-range optical links using OM2 and OM3 will be presented here.
In the transmission shorter than 300 m using silicabased MMFs, the effects of chromatic dispersion is small
while the bandwidth limits due to mode dispersion isdominant, so that the bandwidth of the MMF at the wavelength in use becomes important. Table 2 shows the
bandwidth of the OM2 and OM3 used in this study. The
1060 nm OFL bandwidth of OM2 is 2262 MHz·km, larger
than those at 850 nm and 1300 nm, and according to theestimation using the IEEE spread sheet, the fiber has a
3 dB penalty distance of 350 m promising a possible
transmission distance longer than 300 m. On the other
hand, although OM3 has a bandwidth of 1094 MHz·km,
smaller than the 850 nm OFL bandwidth due to the factthat the fiber is optimized for 850 nm, the fiber is estimated to have a transmission distance longer than 150 m.
Table 2

OFL bandwidth of OM2 and OM3 used.

Category

850 nm/1300 nm OFL
Bandwidth1060 nm OFL
Bandwidth

OM2

850 nm, 789.9 MHz·km
1300 nm, 1602.4 MHz·km

2262 MHz·km

OM3

850 nm, 4509 MHz·km
1300 nm, 708 MHz·km

1094 MHz·km

Figures 14 and 15 show the BER characteristics of
1 µm-range optical links using OM2 and OM3. Both OM2
and OM3 have been confirmed to provide error-free trans–12
mission with BER=10 , from BTB to 300 m. The power
penalty of the OM2 at 300 m transmission is less than 2
dB, demonstrating some power budget margin for 300 m
transmission. Since OM3 increases in transmission power
penalty by more than 2 dB, from 150 m to 300 m, thetransmission limit is estimated to be around 300 m. But
up to 150 m, it can be seen that the fiber has some powerbudget margin. Thus it has been demonstrated that the
1 µm-range optical links using OM2 and OM3 are fully

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Low Power Consumption 10 Gbps×12 ch Parallel Optical Module for Optical Interconnection

capable of transmission up to 150 m, and that the opticallink using OM2 is applicable to up to 300 m.

BTB
50m
10−4

100m

1 µm-range has been achieved, together with the 300 m
transmission using the OM2 and OM3 fibers demonstrating that the 1 µm-range optical link is appropriate toextensive applications. In view of the current trend toward
lower power consumption, we intend to promote productdevelopment in response to the increasing needs for optical interconnects, taking advantage of the features of
1 µm-range including low power consumption.

150m

BER

300m
10

−6

REFERENCES

10−8

10−10
10−12
-18

-16

-14

-12

-10

-8

Average received optical power（dBm）

Figure 14 BER characteristics after OM2-MMF transmission.
BTB
50m
10−4

100m
150m

BER

300m
10−6

10−8

10−10

10−12
-18

-16

-14

-12

-10

1) H. Nasu: “100Gbps for $100, 1 µm-wavelength-range optical interconnects employing high-density parallel-optical modules,” OFC/NFOEC, Workshop OMA, (2009).
2) SNAP12 Multi-Source Agreement, Rev 1.1, (2002).
3) IEEE standards 802.3ae, Jun. 2002.
4) K. Takaki et al.: “A recorded 62% PCE and low series and thermal
resistance VCSEL with double intra-structure,” IEEE International
Semiconductor Laser Conf., PD1.1, Sept. (2008)
5) K. Takaki et al.: “Experimental demonstration of low-jitter performance and high-reliable 1060 nm VCSEL arrays for 10 G×12 ch
optical interconnection” SPIE Photonics West, 7615-01 (2010)6) T. Ishikawa et al.: “High-density and low-cost 10 Gbps×12 ch optical modules for high-end optical interconnect application,” OFC/NFOEC, OMK6, (2008).
7) J. Sasaki et al.: “PETIT: a compact 40 Gb/s optical interface module
for multi-terabit backplane interconnects,” OECC, 6F4-2, (2005),
340-341.
8) The Green 500, http://www.green500.org/.
9) Thomas Aggerstam et al.: “Large Aperture 850 nm Oxide-Confined
VCSELs for 10 Gbps Data Communication,” SPIE, 4649, (2002),
19-24.
10) N. Suzuki et al.: “1.1 µm-range InGaAs VCSELs for high-speed
optical interconnections,” IEEE PTL, 18, no.12, (2006), 1368-1370.
11) JIS C 6802:0000 (IEC 60825-1:2001)12) H. Nasu et al.: “Very low power of<7mW/Gbps, 1060 nm 120 Gbps
optical link employing high-density parallel-optical module,” ECOC,(2009), P6.17
13) Nasu et al.: “120 Gbit/s parallel optical module with electrical pluggable socket,” IEICE, Society Conference, 2008, C-3-4. (inJapanese)
14) Yoshihara et al.: “Low power consumption 10 Gbps×12 ch parallel
optical module using 1.1 μm band,” IEICE, Society Conference,
2009, C-3-54. (in Japanese)
15) IEEE 802.3z link model spreadsheet, rev.3.1.16a,		 10 GEPBud3_1_16a.xls.

-8

Average received optical power（dBm）

Figure 15 BER characteristics after OM3-MMF transmission.

6.

CONCLUSIONS

We have developed a compact 10 Gbps×12 ch parallel
optical module capable of high-density mounting, targeted at board-to-board optical interconnects. By using the
1 µm-range VCSEL array, PD array and low-power consumption ICs based on the BiCMOS technology, a low
power consumption of 7 mW/Gbps has been achieved inpaired TX-RX 12-channel simultaneous transmission. The
1 km transmission using an MMF optimized in the

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