Photonic crystal surface-emitting lasers (PCSELs), which use a two-dimensional photonic crystal as the laser cavity, can achieve both high output powers and narrow beam divergence angles owing to single-mode lasing over a large area. High-speed, high-power, direct modulation of PCSELs is expected to realize compact and power-saving optical transmitters without bulky lens systems and fiber amplifiers for free-space optical communications. In this paper, we realize high-speed, high-power, free-space optical communication via directly modulated watt-class photonic-crystal surface-emitting lasers. We first numerically investigate the intrinsic (optical) and parasitic (electrical) frequency response characteristics of watt-class PCSELs with large lasing areas, and we show that several-GHz-class direct modulation is feasible even in watt-class PCSELs. Then, we fabricate a 500-µm-diameter PCSEL and simultaneously realize watt-class continuous-wave operation and several-GHz-class direct modulation. Finally, by directly modulating the developed PCSEL with a quadrature amplitude modulation (QAM) signal, we demonstrate free-space optical communication with over 10 Gbit/s high-speed transmission and virtual 5-km-class long-distance transmission even without using a transmitter lens.

中文翻译：

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通过直接调制瓦特级光子晶体表面发射激光器进行高速高功率自由空间光通信


光子晶体表面发射激光器（PCSEL）使用二维光子晶体作为激光腔，由于在大面积上产生单模激光，因此可以实现高输出功率和窄光束发散角。 PCSEL 的高速、高功率、直接调制有望实现紧凑且节能的光发射机，无需笨重的透镜系统和光纤放大器，用于自由空间光通信。在本文中，我们通过直接调制瓦特级光子晶体表面发射激光器实现了高速、高功率、自由空间光通信。我们首先对具有大激光面积的瓦特级 PCSEL 的固有（光学）和寄生（电）频率响应特性进行数值研究，结果表明，即使在瓦特级 PCSEL 中，数 GHz 级直接调制也是可行的。然后，我们制造了直径为 500 µm 的 PCSEL，并同时实现了瓦特级连续波操作和数 GHz 级直接调制。最后，通过直接用正交幅度调制（QAM）信号调制所开发的PCSEL，我们演示了即使不使用光调制器也能实现超过10 Gbit/s高速传输和虚拟5公里级长距离传输的自由空间光通信。发射器镜头。