Degradation of fiber optical communication devices under damp-heat aging

Failure mechanism of hermetically sealed fiber optical communication devices under damp-heat aging (85/spl deg/C and 85% relative humidity) is discussed linked to degradation of physical properties of the cured epoxy, i.e., glass transition temperature, coefficient of thermal expansion, and adhesion. Recovery of output power or insertion loss from the degraded devices is reported after baking at a certain temperature. This reversible phenomenon is attributed to moisture absorption under the test condition and desorption at high temperature bake. This letter demonstrates that a correlation exists between the performance of optical communication devices and physical properties of the cured epoxy used for the subassembly.