Owing to advances in fabrication technology and device design, semiconductor optical amplifiers (SOAs) are evolving as a promising candidate for future optical coherent communication links. This review article focuses on the fundamentals and broad applications of SOAs, specifically for optical channels with advanced modulation formats, as an integrable broadband amplifier in commercial transponders and as a nonlinear medium for optical signal processing. We discuss the basic functioning of an SOA and distortions of coherent signals when SOAs are used as amplifiers. We first focus on the techniques used for low-distortion amplification of phase-modulated signals using SOAs. Then we discuss optical signal processing techniques enabled by SOAs with an emphasis on all-optical wavelength conversion, optical phase conjugation, and phase quantization of coherent optical signals.

中文翻译：

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半导体光放大器：最新进展和应用

由于制造技术和器件设计的进步，半导体光放大器 (SOA) 正在发展成为未来光相干通信链路的有希望的候选者。这篇评论文章重点介绍 SOA 的基本原理和广泛应用，特别是对于具有高级调制格式的光通道、作为商业转发器中的可集成宽带放大器以及作为光信号处理的非线性介质。我们讨论了 SOA 的基本功能以及当 SOA 用作放大器时相干信号的失真。我们首先关注用于使用 SOA 对相位调制信号进行低失真放大的技术。然后我们讨论了 SOA 支持的光信号处理技术，重点是全光波长转换、光相位共轭、