download

Evaluating the reliability of optical connectors
7
The optical characteristics of the optical connectors reviewed for this study were
automatically measured during the High Temperature Storage Test (Damp Heat) (at
85°C and 85 percent relative humidity for 1000 hours) and the Temperature Cycling Test
(at 85°C / -40°C for 500 cycles of one hour each). We obtained the following results.
(1)No changes occurred in optical characteristics, but pistoning increased in the
connectors.
(2)Increased pistoning of the ferrule tips was observed in both the Temperature Cycling
Test and the High Temperature Storage Test (Damp Heat), but the major changes
occurred in the Temperature Cycling Test.
(3)The post-test condition of the ferrule tips after testing at 85°C and 85 percent relative
humidity for 2000 hours exhibited flattening distortion. This result could indicate that
the actual pistoning was greater than the calculated amount.
8
Conclusion
Topics for future discussion
Many aspects of the relationship between pistoning and optical characteristics have yet
to be confirmed, and topics such as manufacturing conditions also require research.
[Terminology]
*1.Telcordia
The breakup of the American communications giant AT&T (Bell Telephone) created
seven regional telephone providers (the so-called "Baby Bells") and established a
research and development company initially called Bellcore. Later, when this
subsidiary was sold to a company unrelated to the original Bell, the company became
known as Telcordia Technologies. In the field of communications in the U.S., the
Telcordia standards are widely referenced as the baseline standards for this field.
*2.SC connectors, and *3. FC connectors
Both of these optical connectors are zirconia ferrule (refer to Fig.2 above) connectors
developed in Japan that are widely used throughout the world. The stationary part of
the SC connector is made of plastic, and can be connected by merely being pressed
on. The stationary part of the FC connector, though, is made of metal and must be
attached with screws.
*4.Insertion loss
The transmission loss occurring when light passes through the part. This value
compares the insertion light with the outgoing light, and is expressed in decibels.
*5.Return loss
This value compares the insertion light power and the reflected light power of the
reflected light returning inside the part. This value is expressed in decibels.
- 10 -
Espec Technology Report No20