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Wire & Cable ASIA – September/October 2007 79
Wir & Cable ASIA – March/April 14
Abstract
UV cured acrylate type coating materials for
mid-temperature optical fibres (operating temperatures
up to +200°C) are considered as a replacement for the
existing silicone type coating materials due to better
manufacturability and handling (stripping, cleaning and
re-coating) properties.
A newly developed coating material demonstrated superior
performance in comparison with the existing commercial
mid-temperature acrylates. Long-term temperature
aging of several fibre samples was used to study fibre
performance at elevated temperatures.
Optical attenuation and fibre strength were measured at
different conditions to confirm the excellent performance
and durability of the new material.
1 Introduction
Telecom grade UV cured acrylate coating materials for
optical fibres are good for operating temperatures up to
85°C in long-term applications but suffer non-reversible
degradation at higher temperatures for prolonged periods.
Today several commercial UV cured acrylate type
coating materials, including primary and secondary
ones, are available for mid-temperature applications at
150°C–180°C.1-4 Single or dual coat designs are available.
Temperature aging of optical fibre by temperature cycling
or constant temperature in normal atmosphere is the
primary experimental method to track coating stability
and to test optical fibre parameters: attenuation and
mechanical strength.
Dynamic thermo gravimetric analysis (TGA) and isothermal
TGA are used to compare different coating materials,
estimate coating material lifetime based on coating weight
loss, and to define the best coating system for a specific
application.
Corning Incorporated has evaluated a new optical fibre
coating material for mid-temperature applications. The
coating is a UV-cured acrylate type material. This material
should preserve long-term optical fibre performance for
bare and cabled fibre.
New coating for mid
temperature optical fibres
By Ching-Kee Chien and Valery A Kozlov, Science and Technology, Corning Inc, USA
❍
❍ Figure 1: TGA test of the new and commercial mid-
temperature coatings at heating rate of 10°C/min
❍
❍ Figure 2: TGA test for single coat fibre sample with new and
commercial materials at heating rate of 20°C/min
Temperature, °C
Weight loss, %
New
Commercial
TGA weight, %
Temperature, °C
New
Commercial
The new coating delivers a high coating adhesion to
glass, which is highly desirable in some mid-temperature
optical fibre applications for better handle ability and
optical performance.
2 New coating material
2.1 Material properties
The newly developed mid-temperature coating is a UV
curable urethane acrylate. A 75-micron thick film cured
at 1 J/cm2 with Fusion D-bulb was measured by a Seiko