CHARACTERISTICS AND STATIC FATIGUE RELIABILITY OF A ZIRCONIA ALIGNMENT SLEEVE FOR OPTICAL CONNECTORS

This paper describes the optical characteristics and static fatigue re liability of a zirconia alignment sleeve, which is a component part of an optical connector with zirconia ferrules. This combination of slee ve and ferrules hardly generates any wear debris during connector inse rtion and removal cycles. This has reduced the cleaning frequency of t he ferrule endface during cycles and greatly improved the return loss stability of the optical connectors. The zirconia alignment sleeve ena bles stable return loss characteristics to be achieved over a wide tem perature range as it has the same thermal expansion coefficient as the zirconia ferrule. Furthermore, the gauge retention force for the zirc onia alignment sleeve is defined with a view to its practical use. Thi s force must be between 2.0 and 3.9 N to allow stable optical connecti ons to be made under various mechanical and environmental conditions. We also clarify the conditions for a proof test by which to prevent th e occurrence of static fatigue fractures in the sleeve, and we confirm the validity of the test. The static fatigue parameters of zirconia c eramics are derived from the static fatigue theory for brittle materia ls and fracture testing. We use these static fatigue parameters to pre dict the lifetime of a zirconia sleeve under working stress. An approp riate stress level for the proof test which eliminates weak sleeves, i s about 3 times greater than working stress. The strength of the sleev e as demonstrated in the proof test is confirmed by accelerative stres s aging. The performance of this sleeve is superior to that of a conve ntional copper alloy sleeve and the proof test confirms its reliabilit y; under 0.1 FIT for 20 years of use.