Dual-Wavelength High-Power Laser Diodes Fabricated by Selective Fluidic Self-Assembly

We have developed dual-wavelength high-power laser diodes (LDs) with a hybrid integrated solution, in which a 660 nm (red) LD chip and a 780 nm (infrared) LD chip are mounted side-by-side on the same substrate. To achieve the required mounting position accuracy, i.e., the distance between two emitting points is limited to 110±3 µm, we have developed a novel mounting technique called selective fluidic self-assembly (S-FSA). In this technique, we used new self-locking structures of guest-host pairs. Bumps formed on the bonding surfaces of the LD chips are used as guests. A substrate with recesses whose shapes correspond to those of the bumps is used as the host. By forming bumps aligned along the waveguide and assigning a rotationally asymmetric shape for the bumps, an accurate and selective mounting is realized. Dual-wavelength LDs fabricated by this technique demonstrated the required positioning accuracy and high-power operation.