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76 Wire & Cable ASIA – March/April 2017
Yunfang Ruan, Zhuang Xiong,
Xiaoli Liu, Wenjing Ye
State Key Laboratory of Optical Fibre and Cable
Manufacture Technology, Yangtze Optical Fibre
and Cable Joint Stock Co Ltd, and Huawei
Technologies Co Ltd
Shenzhen, Guangdong, China
Wuhan, Hubei, China
Tel: +86 27 67887520
Email:
Before the experiment, record the attenuation of each fibre
at room temperature (23°C).
After that, put the cable into the temperature cycling
chamber to perform the temperature cycling test.
4.2 Temperature cycling programme
1 Lower the temperature from 23°C to -40°C within
30 minutes and hold this temperature for 12 hours.
Perform attenuation measurement
2 Raise the temperature to 70°C within 30 minutes
and hold it for 12 hours. Perform attenuation
measurement
3 Return the temperature to 23°C within 30 minutes
and hold this temperature for 12 hours. Perform
attenuation measurement
4.3 Results and analysis
Check the end caps at -40°C. Some ice can be found
around them.
Therefore, the experiment has successfully simulated the
situation where water freezes around end caps, as shown
in Figure 5.
Pay much attenuation to the positions where the end
caps are located on the attenuation curves during
measurement.
All the OTDR curves are very smooth.
Figure 6 shows the largest attenuation values at -40°C, at
1,310nm and 1,550nm wavelengths respectively.
After the test, attenuation changes of all fibres are
really small and no visual damage to the cable sheath has
been found.
5 Conclusion
When micro-duct air-blown cables are used in cold
areas, the influence of freezing condition on optical fibre
transmission should be taken into consideration.
In order to study this subject, two experiments are
designed to evaluate such influence.
Based on the test results in this paper, it can be concluded
that the effects of frozen water on micro-duct air-blown
cables are insignificant.
However, the long-term effect during the cable lifetime
should be also considered and further investigated.
Thus, protective measures to avoid the penetration of
water into micro-ducts should not be ignored.
6 References
1 IEC 60794-1-22 Optical fibre cables – Part 1-22: Generic specification
– Basic optical cable test procedures – Environmental test methods
2 IEC 60794-5-10 Optical fibre cables – Part 5–10: Outdoor microduct
optical fibre cables, microducts and protected microducts for
installation by blowing
Paper courtesy of the 64th IWCS Technical Symposium,
Atlanta, Georgia, USA, October 2015.