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Low-Count Optical Premises Cable for Easy Installation

INTRODUCTION

Optical premises cables with one to eight fiber counts are
typically used for optical fiber installation in private residences and the premises of medium-sized housing complexes. When conventional optical premises cables are to
be installed in limited spaces and meandering routes or incertain cable ducts occupied by existing cables, concerns
are raised such that a lead-in work would become difficult
due to a large friction resistance, and that cable reliability
would degrade due to abrasion of the sheath material.
Also, conventional cables usually use a steel wire or
aramid fiber-based FRP for their strength member. Whilea steel wire would make installation in small bending radius difficult and increase the weight, an aramid FRP would
break when pulled with a high tension and degrade thereliability of optical fiber, because of its small allowablestrength.
To solve these problems, we have recently developed a
new optical premises cable with one, two, four and eightcores. The cable uses an abrasion-resistant, low-friction
PE material for the sheath, together with a poly(pphenylenebenzobisoxazole) (PBO)-based FRP materials
for the strength member, which is comparable to steel
wire in strength, and yet is equivalent to aramid FRP inbendability and mass.

2.

mass of the strength member, as well as the allowabletensile strength of the cable. It is seen that the cable using
PBO FRP material has the characteristics that combine
the advantages of steel wire and aramid FRP.

3.

STRUCTURE

Figure 3 shows the cross-sections of the cable. Everytype of cable adopts FlexiWave fiber having a small allow-Load FP
Test sample

Test sample
Tension（FD）（ﬁxed）

Friction coeﬃcient（relative value）

1.

100%
80%
60%
40%
20%
0%

Conventional
cableDevelopedcable

Dynamic friction coeﬃcient μ0= FD/FP

Figure 1

Evaluation of frictional force between cables (1 core).

FEATURES

The optical premises cable developed here has the following characteristics:
2.1 Low Friction
Figure 1 shows the test method and the evaluation resultsfor dynamic friction coefficients between two sliding
cables. It can be seen that the cable developed here
reduces the frictional force between cables by 60 to 70 %.
2.2 High Abrasion Resistance
The abrasion resistance of the new cable has been significantly improved by increasing the strength of the sheathmaterial together with by reducing its frictional coefficient.
Figure 2 shows the test method for abrasion resistance(JIS C 3005 compliant), and Table 1 the test results.
2.3 High Strength and Handling Performance
Table 2 shows the Young’s modulus, bending rigidity andTest sample
300 mmφ350-mm abrasion disk
Rotational speed: 60 turns/min
Material: Silicon carbide, 36 in grain size

LoadFigure 2Abrasion resistance test method.

Table 1

Test results of abrasion resistance.

Abrasion loss
at 2000 turns

Conventional cable

Developed cable

1 mm or more in depth,exposing fibers

Approx. 0.20 mm

Furukawa Review, No. 33

200812Low-Count Optical Premises Cable for Easy Installation

able bending radius of R=15 mm, as well as the sameouter diameter as for the conventional counterpart so as
to be adapted to the existing peripheral connecting components.

4.

Table 3 shows the cable characteristics, indicating thatthe cable has superior performance equivalent to that ofconventional cables.

5.
Table 2φ0.4-mm
steel wire

φ0.5-mmaramid FRPYoung’s modulus of strength
member (MPa)

270

200

109Bending rigidity at bending
diameter of 30 mm (N) *

1.4

1.9

1.3

Mass (kg/km)

8.8

9.7

8.2

Allowable tensile strength (N)

156

151

62

CONCLUSION

We have developed the low-count optical premises cablethat is superior to conventional cables in terms of reduced
friction, improved abrasion resistance and upgraded
strength.

Tensile strength and handling performance of cables.
φ0.5-mm
PBO FRP

CHARACTERISTICS

For more information, please contact:
Telecommunications Engineering Dept.,
Telecommunications Co.		 TEL: +81-3-3286-3440
FAX: +81-3-3286-3190* Measured under IEC60794-1-2 compliant cable conditions.
Note: Horizontal comparison of colored fields shows that PBO FRP combines the advantages of steel wire and aramid FRP.

φ0.25‑mm FlexiWave ﬁber

φ0.25‑mm FlexiWave ﬁber

φ0.5‑mm PBO FRP

φ0.5‑mm PBO FRP

One-core optical premises cableTwo-core optical premises cable（Size: 2×3.1 mm）（Size: 2×3.1 mm）

QS4 ribbon（FlexiWave ﬁber）

Two QS4 ribbons（FlexiWave ﬁber）

φ0.5‑mm PBO FRP

φ0.5‑mm PBO FRP

Four-core optical premises cable

Eight-core optical premises cable（Size: 2×3.7 mm）（Size: 2 x 3.7 mm）* Sheath material: Halogen-free, abrasion-resistant, low-friction, ﬂame-retardant polyoleﬁn

Test item
Transmission loss
(dB/km)Figure 3

Cross sections of cables.

Table 3

Cable characteristics.
One-coreTwo-core

Four-core

Eight-coreat λ=1.31 µm

Test condition＜ 0.35 dB/km＜ 0.34 dB/km＜ 0.34 dB/km＜ 0.34 dB/km

at λ=1.55 µm＜ 0.20 dB/km＜ 0.21 dB/km＜ 0.21 dB/km＜ 0.22 dB/km

Tensile testat 150 N(loss increase in dB)＜ 0.1 dB

＜ 0.1 dB

＜ 0.1 dB

＜ 0.1 dB

Bending test
R=15 mm x 10 cycle (one-core, two-core)(loss increase in dB) R=30 mm x 10 cycle (four-core, eight-core)＜ 0.1 dB

＜ 0.1 dB

＜ 0.1 dB

＜ 0.1 dB

Lateral pressure test 1200 N / 25 mm (one-core, two-core)(loss increase in dB) 1960 N / 100 mm (four-core, eight-core)＜ 0.1 dB

＜ 0.1 dB

＜ 0.1 dB

＜ 0.1 dB

Impact test
300 g × 1 m(loss increase in dB)＜ 0.1 dB

＜ 0.1 dB

＜ 0.1 dB

＜ 0.1 dB

＜ ±0.02 dB/km＜ ±0.02 dB/km＜ ±0.03 dB/km＜ ±0.03 dB/km

Heat cycle test
⊖30～70℃, 10 cycle(loss change in dB/km)
Flame retardancy

JIS C 3005, tilted sample

Spontaneously extinguished Spontaneously extinguished Spontaneously extinguished Spontaneously extinguished

JIS C 3521, vertical tray

Damaged length < 1.8 m Damaged length < 1.8 m Damaged length < 1.8 m Damaged length < 1.8 m

Note: Loss increases for mechanical tests are measured atλ=1.55 μm.

Furukawa Review, No. 33

200813