Low cost uncooled mini-DIL module for pump laser

This paper describes a low cost uncooled, 8 pin mini-dual inline (DIL) module for a medium power 980 nm pump laser. In this low cost pump laser module, an innovative approach was adopted on the module design. This design allows the use of conventional pick-and place equipment to load all the components (except the fiber pigtail) in one pass. These components are then reflowed in a vacuum chamber to achieve the attachment in one step without the need for any flux. The most crucial and time-consuming assembly step is the fiber-to-laser diode coupling and attachment. An automatic active alignment system was used to achieve the most efficient coupling between laser diode and fiber. Laser welding was then utilized to hold that coupling position. This pump laser module has achieved coupling efficiencies of 80% at optimum alignment. The module is able to maintain the coupling efficiencies within 10% peak coupling efficiency in its operation temperature range of -5 to 70°C. The pump laser module is under qualification to the requirements of Telcordia-468, including temperature cycling, high temperature operating life, vibration and shock. This paper covers the module design, process flow, optical coupling simulation, thermomechanical simulation and design optimization, coupling efficiency measurement and its change with environmental conditions.