Design and qualification of hermetically packaged lithium niobate optical modulator

Applications for lithium niobate modulators have developed in CATV, telephone and data communications markets. With deployment of devices in these systems comes the need to ensure long term reliability. In this paper we described the design, assembly, and qualification of a hermetically packaged optical modulator. The qualification devices were fabricated using a pilot production facility running at Lucent Technologies-Bell Laboratories. A variety of techniques are used to hermetically seal the Kovar package. The effects of thermal expansion mismatch between the package and the die are managed by careful package design and assembly operations. The package assembly employs a modular design which allows qualification of the subassemblies as well as the entire modulator. This design modularity allows fiber subassemblies and the lithium niobate die to be characterized for optical and mechanical performance before they are incorporated into the packaged modulator