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Development of Optical Indoor Cables Using 0.9-mm
Tight-Buffered Optical Fiber

1.

2.

INTRODUCTION

With the rapid growth of broadband services, recent years
have seen full-fledged implementation of optical services
aimed at ordinary houses, as well as at office buildings
and apartment buildings. Figure 1 shows a layout example of optical indoor cables in apartment buildings.
Indoor cable

CABLE STRUCTURE

Figure 2 shows a cross-section of the cable developed
here. Two types of cables were developed, one using
FlexiWave single-mode (SM) fiber having an allowablebending radius of 15 mm, and one using LaserWave
multi-mode (MM) fiber having the same allowable bending radius of 15 mm. The indoor cable measuring 2.5 mm
x 4.5 mm in outer shape is formed by arranging two
strength members in parallel on the both sides of 0.9-mm
tight-buffered optical fibers, then applying a flame-retardant halogen-free sheath.
4.5 mmSteel wire

2.5 mmLongitudinalcable

Flame-retardant halogen-free sheath
0.9-mm tight-buﬀered optical ﬁber

Figure 2

Cable cross-section.

ONU

Figure 1

Typical layout of optical indoor cables in apartmentbuildings.

Optical fibers from a trunk cable are first accommodated in the main distributing frame (MDF) room, and there
they are branched for wiring to each room. Here, indoor
cables are used mainly for floor wiring. Then the opticalfiber led into each room is connected via optical network
unit (ONU) to personal computers and the like.
In such wiring work, high efficiency enabling large volume of work in a short time is required in addition toassuring function and quality. Accordingly, aiming at easeof wiring work and minimal skill requirement, we havedeveloped indoor cables using a 0.9-mm tight-bufferedoptical fiber, placing importance on handling performanceand ease of work.

3.

CABLE FEATURES

3.1 Structure of Tight-Buffered Fiber
Although the diameter of an optical fiber generally used is0.25 mm, this could lead to breaking due to poor visibility
and inadvertent hooking during wiring work. Accordingly,
to allow easy wiring work with a sense of security, handling performance has been improved by coating thecore fiber to 0.9 mm in diameter using a high-strengththermoplastic resin.
Also, since the core fibers at cable ends must be terminated with a connector or fusion spliced at the time ofcable laying, a suitable coating material has been selected to provide good removability of coating.

Furukawa Review, No. 35

200931

Development of Optical Indoor Cables Using 0.9mm Tight-Buffered Optical Fiber

Table 1
Optical ﬁber

Characteristics of single-mode fiber cable.

Test item

Test condition

0.9-mm thermoplastic resin coating

Figure 3

Comparison between 0.25-mm fiber and 0.9-mm
tight-buffered fiber.

SM fiber (FlexiWave)

1310 nm≦ 0.36 dB/km

1550 nm≦ 0.22 dB/km

Bending

R=15 mm, ±90°

≦ 0.05 dB

Crush

1200 N / 25 mm, 1 min≦ 0.05 dB

Impact0.3 kg, 1 m≦ 0.05 dB

Twist±90°/m≦ 0.05 dBTension

200 N≦ 0.05 dB

Temperature cycling-20~60℃, 10 cycle≦ 0.10 dB/km

Transmission loss

0.25-mm UV resin coating

Test result

Temperature/humidity aging (I) 45℃･95%, 168 hr≦ 0.10 dB/km

Temperature/humidity aging (II) -10~25~65℃･93%, 10 cycle ≦ 0.10 dB/km

3.2 10-Gbps Transmission CapabilityThe MM fiber-based cable uses our LaserWave fiber suitable for 10-Gbps transmission. The LaserWave fiber
allows 10-Gbps transmission for up to 600 m, making
itself suitable for LAN wiring in office buildings and apartment buildings.
Figure 4 shows the result of 10-Gbps transmission tests
over a 600-m indoor cable that uses LaserWave fiber. The
transmitted waveform meets the standards of IEEE
802.3ae, demonstrating that the 10-Gbps signals havebeen properly transmitted even for a distance of 600 m.
Moreover, bit error rate (BER) measurements were conducted at 10 Gbps, and it has been confirmed that theBER is 1x10-12 or lower as specified by the IEEE 802.3ae.

Flammability

JIS C 3005, inclined

Fiber accessibility

Tear off and take out by hand Good

Self-extinguishing

Fiber protrusion-20~60℃

Coating stripping force

20-mm removing using a tool ≦ 20 N

≦ 0.2 mm

•Wavelength for optical characteristics measurement is 1550 nm.
•The table above shows typical values, not guaranteed values.

Table 2

Characteristics of multi-mode fiber cable.

Test item

Transmission loss

Test condition

Test result
MM fiber (LaserWave)

850 nm

≦ 2.30 dB/km

1300 nm≦ 0.60 dB/km

Differential mode delay (DMD) IEC 60793-2-10, Ed 2.0

Templates 1~6 satisfiedBending

R=15 mm, ±90°

≦ 0.10 dB

Crush

1200 N / 25 mm, 1 min≦ 0.10 dB

Impact0.3 kg, 1 m≦ 0.10 dB

Twist±90°/m≦ 0.10 dBTension

200 N≦ 0.20 dB

Temperature cycling-20~60℃, 10 cycle≦ 0.20 dB/km

Temperature/humidity aging (I) 45℃･95%, 168 hr≦ 0.20 dB/km

Temperature/humidity aging (II) -10~25~65℃･93%, 10 cycle ≦ 0.20 dB/km

Figure 44.

10-Gbps waveform.

Flammability

JIS C 3005, inclined

Self-extinguishing

Fiber accessibility

Tear off and take out by hand Good

Fiber protrusion-20~60℃

Coating stripping force

20-mm removing using a tool ≦ 20 N

≦ 0.2 mm

•Wavelength for optical characteristics measurement is 850 nm.
•The table above shows typical values, not guaranteed values.

CHARACTERISTICS

The characteristics of the indoor cable developed areshown in Tables 1 and 2.
The general mechanical and temperature characteristics required of an indoor cable have been confirmed.
Also, with respect to flammability property, the cable has
passed the 60° inclined flaming test specified by JIS C3005.
Moreover, good results have been confirmed in terms ofcore fiber accessibility and removability of core fiber coating.

5.

CONCLUSIONS

Optical indoor cables using a 0.9-mm tight-bufferedfiber have been developed, achieving better cable laying
efficiency than before.
For more information, please contact:
Telecommunications Engineering Department,
Telecommunications Co.		 TEL: +81-3-3286-3325
FAX: +81-3-3286-3708

Furukawa Review, No. 35200932