Abstract

Photonic integrated circuits capable of high-speed, large-capacity communications at low cost and low power consumption are attracting attention in a situation where communication traffic is expected to increase due to the expansion in data centers and new services using B5G/6G wireless networks in which technology development is advancing[1]. Under such a background, optical devices having a quantum dot (QD) structure are expected to be applied not only to laser diodes (LDs) and semiconductor optical amplifiers, but also to monolithic and heterogeneous photonic integrated circuits[2]. So far, we have reported the single-mode CW operation of a QD-DFB-LD in the 1.55 μm band at room-temperature [3]. In this paper, we report we fabricated a 1.55 μm-band QD-DFB-LD with a possibly unprecedented multi-stacked structure, such as 25 layers, and the obtained characteristics were much better than the results we reported previously.

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