Laser microwelding for fiber-chip coupling modules with tapered standard monomode fiber ends for optical communication systems

Abstract

We design a welding machine for fabricating butterfly (BFY) modules with an optical coupling setup that is well suited for rapid prototyping and small-scale production of InP and GaAs-based waveguide-fed photonic components such as diode lasers, semiconductor amplifiers, optical modulators, and optoelectrical ICs (OEICs). The light of these devices is transferred very efficiently into single-mode fibers using integrated tapered lensed ends. In our setup the mechanical adjustment of the fiber-chip coupling is done semiautomatically by a newly designed coupling machine while welding performs the fixing of the fiber-chip connection. We found a yield of 47% within a shift of 1.0 μm at the initial welding spot. With additional weld adjustment, it was possible to extend the yield of 67%. We introduce, to our knowledge for the first time, an adjustable welding technique, which we call strain-reducing welding, which has several benefits in comparison to the well-known laser hammering technique.