Development of High Temperature Fiber and ETFE Tight Buffered ...

The test is used to examine the fiber’s resistance to rapid
temperature changes, to determine the reliability and stability of
its optical performance, and to improve the product quality.
Figure 1 and Figure 2 show induced attenuation changes at
1310nm and 1550nm respectively during the thermal shock test.
The maximum change of attenuation in the test at 1310nm
wavelength is +0.008dB/km while that at 1550nm wavelength is
+0.011dB/km.
2.2 Temperature cycling test
Figure 3 and Figure 4 show induced attenuation changes at
1310nm and 1550nm during the temperature cycling test. The
maximum change of attenuation in the test at 1310nm wavelength
is +0.009dB/km while that at 1550nm wavelength is
+0.011dB/km.
Temperature(℃)
Temperature(℃)
A7305109AB1(Silicone&KS2-004)-TCT-1310nm
210
180
0.05
0.04
150
0.03
120
0.02
90
0.01
60
0
30
-0.01
0
-0.02
-30 0 11 22 33 -0.03
-60
-0.04
-90
-0.05
Time(h)
Temperature Change of attenuation
Figure 3. Induced attenuation change at 1310nm in
temperature cycling test
A7305109AB1(Silicone&KS2-004)-TCT-1550nm
Change of
attenuation(dB/km)
210
180
0.05
0.04
150
0.03
120
0.02
90
0.01
60
0
30
-0.01
0
-0.02
-30 0 11 22 33 -0.03
-60
-0.04
-90
-0.05
Time(h)
Temperature Change of attenuation
Figure 4. Induced attenuation change at 1550nm in
temperature cycling test
3. ETFE Tight Buffered Fiber
An ETFE buffer is extruded on the fiber to 900µm in diameter, as
shown in Figure 5.
Figure 5. Structure of ETFE tight buffered fiber
The selection of buffer polymer is very important in the
development of high temperature tight buffered fibers. The
coating and the buffer may be mechanically removed from the
fiber in one step, which is convenient for direct termination with
connectors. Mechanical stripping in short length (about 15mm) is
Change of
attenuation(dB/km)
also permitted to remove the buffer and leave the coating intact,
which can facilitate the splicing with 250μm fibers from gel-filled
cables with loose tube structure.
In this section, the properties of ETFE resin are introduced.
Thermal shock test, temperature cycling test and ageing test are
performed on the tight buffered fiber. Test conditions are shown
in Table 3.
Table 3. Test conditions
Test Item
Thermal
shock test
High Temp.
(°C)
Low Temp.
(°C)
Humidity
(%)
150 -60 --
TCT 150 -60 55
Ageing test 150 -- --
Details of Test
Requirements
Without tension,
attenuation is measured.
Then thermal shock test
is carried out. Keep at
both temperature
extremes for 30
minutes. After that,
attenuation is monitored
online.
3 cycles, 1°C /min,
attenuation is monitored
and recorded
automatically.
Strippability is tested
after TCT.
Without tension,
duration is 30 days.
Attenuation is measured
once a week.
Strippability is tested
after ageing test.
3.1 Properties of ETFE Resin
ETFE (Ethylene tetrafluoroethylene) is used for the
applications requiring good impact resistance and stress cracking
resistance. The resin maintains these properties even at
continuous working temperature over 150°C. These features make
ETFE an excellent candidate for the materials used in chemical or
mechanical industry.
The main properties of ETFE are:
• Excellent impact resistance;
• Enhanced durability and stiffness against other fluoropolymers;
• Higher pressure rating than other fluoropolymers;
• Higher tensile strength and creep resistance than other
fluoropolymers;
• Better crush resistance than other fluoropolymers.
Additional Properties of ETFE are:
• Sterilizable by Gamma ray, ETO and e-beam;
• Working temperature up to 150°C;
• Chemical resistant;
• Flame retardancy: UL-94 V0;
• Limiting oxygen index: 30.
Due to its excellent flame retardancy and good flexibility at low
temperature as well as the retention of properties after ageing at
elevated temperatures up to 150°C, ETFE is the best RoHS
compliant polymer for fiber protection as the tight buffer. The
comparison of different tight buffer materials is shown in Table 4.
International Wire & Cable Symposium 432 Proceedings of the 58th IWCS/IICIT