1.3-μm spot-size converter integrated laser diodes (SS-LDs) for access network applications

We have developed spot-size converter integrated laser diodes (SS-LDs) that include a mechanism for matching the optical field with the fiber and the planar lightwave circuit (PLC). We report the achievement of: reproducible lasing characteristics from 2-inch wafers; stable characteristics up to high temperature; and long-term stability at 85°C. The taper-layer in the SS region is butt-jointed to the active layer. The merit of the butt-joint structure is that it allows the independent structural optimization of the active and SS regions. The active layer consists of compressive strained multi-quantum-well (MQW) structure with 8 wells to increase the maximum operation temperature effectively. The strain is 1.2% in InGaAsP wells, which are 6-nm thick. The taper layer consists of a 1.1-μm-bandgap bulk layer. The taper-layer thickness changes exponentially from the butt-joint portion to the front facet, which effectively reduces radiation loss in the SS region