The combination of grating-based frequency-selective optical feedback mechanisms, such as distributed feedback (DFB) or distributed Bragg reflector (DBR) structures, with quantum dot (QD) gain materials is a main approach towards ultrahigh-performance semiconductor lasers for many key novel applications, as either stand-alone sources or on-chip sources in photonic integrated circuits. However, the fabrication of conventional buried Bragg grating structures on GaAs, GaAs/Si, GaSb, and other material platforms has been met with major material regrowth difficulties. We report a novel and universal approach of introducing laterally coupled dielectric Bragg gratings to semiconductor lasers that allows highly controllable, reliable, and strong coupling between the grating and the optical mode. We implement such a grating structure in a low-loss amorphous silicon material alongside GaAs lasers with InAs/GaAs QD gain layers. The resulting DFB laser arrays emit at pre-designed 0.8 THz local area network wavelength division multiplexing frequency intervals in the 1300 nm band with record performance parameters, including sidemode suppression ratios as high as 52.7 dB, continuous-wave output power of 26.6 mW (room temperature) and 6 mW (at 55°C), and ultralow relative intensity noise (RIN) of $<-165\mathrm{dB}/\mathrm{Hz}$ (2.5–20 GHz). The devices are also capable of isolator-free operating under very high external reflection levels of up to $-12.3\mathrm{dB}$ while maintaining high spectral purity and ultralow RIN qualities. These results validate the novel laterally coupled dielectric grating as a technologically superior and potentially cost-effective approach for fabricating DFB and DBR lasers free of their semiconductor material constraints, which are thus universally applicable across different material platforms and wavelength bands.

中文翻译：

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具有横向耦合介质光栅的高性能分布式反馈量子点激光器

将基于光栅的频率选择光学反馈机制，如分布式反馈 (DFB) 或分布式布拉格反射器 (DBR) 结构与量子点 (QD) 增益材料相结合，是实现许多关键的超高性能半导体激光器的主要方法新颖的应用，作为光子集成电路中的独立源或片上源。然而，在 GaAs、GaAs/Si、GaSb 和其他材料平台上制造常规掩埋布拉格光栅结构遇到了重大的材料再生困难。我们报告了一种将横向耦合介电布拉格光栅引入半导体激光器的新颖且通用的方法，该方法允许光栅和光学模式之间的高度可控、可靠和强耦合。我们在具有 InAs/GaAs QD 增益层的 GaAs 激光器旁边，在低损耗非晶硅材料中实现了这种光栅结构。由此产生的 DFB 激光器阵列在 1300 nm 波段以预先设计的 0.8 THz 局域网波分复用频率间隔发射，具有创纪录的性能参数，包括高达 52.7 dB 的边模抑制比，26.6 mW 的连续波输出功率（房间温度）和 6 mW（在 55°C 时），以及超低相对强度噪声 (RIN)$<-165\mathrm{D\; b}/\mathrm{赫兹}$（2.5–20 GHz）。这些器件还能够在高达高达的外部反射水平下进行无隔离器操作$-12.3\mathrm{D\; b}$同时保持高光谱纯度和超低 RIN 质量。这些结果验证了新型横向耦合介电光栅是一种技术优越且具有潜在成本效益的方法，用于制造不受半导体材料限制的 DFB 和 DBR 激光器，因此普遍适用于不同的材料平台和波长带。