Versatile butt-joint regrowth for dense photonic integration

Abstract

Butt-joint regrowth is widely used in photonic integration, but it has been challenging to break the density-quality tradeoff due to the edge growth rate enhancement (GRE) effect. In this work, we propose a scheme to circumvent this tradeoff by using large regrowth masks whose centers are exposed to epi-growth for neutralization of the excessive species. With the GRE under control, epi-stacks with arbitrarily large sizes supporting dense arrays can be butt-joint integrated with minimal compromise to their epitaxy quality. In our experiment, multi-quantum-well-based material of an exceptionally large area of 0.5 × 1.7 mm2 was epitaxially integrated with passive InP material on the same wafer. A more than 20 × reduction in edge topology compared to conventional methods was achieved.

Scaling photonic integrated circuits with InP technology: A perspective

“…A butt-joint regrowth technique has been developed for arbitrary active component separation using an innovative open-mask approach. 167,168 The conceptual process flow of such open-mask butt-joint regrowth is illustrated in Fig. 8(a).…”

“…As a preliminary verification, a 0.5 × 1.7 mm 2 MQW-based active area is integrated with a passive i-InP material in the same horizontal plane using this technique. 167 Figure 8(b) shows the cross-sectional SEM image of such a butt-joint structure. The growth rate enhancement measured is of the same level as narrow stripes of 10 μm width.…”

High Density Integration of Semiconductor Optical Amplifiers in InP Generic Photonic Integration Technology

“…However, this large spacing between active components limits significantly the capability for high density integration. Recently, a new BJR fabrication scheme has been proposed to fabricate arbitrarily large areas of active material [23]. This method enables the fabrication of dense arrays of active devices.…”