瑞士洛桑联邦理工学院Tobias J. Kippenberg团队研制了一种基于光子芯片的超宽带参量放大器。该项研究成果发表在2025年3月12日出版的《自然》杂志上。

光放大对现代通信至关重要，主要依赖于掺铒光纤放大器（EDFA）。然而，EDFA仅覆盖光纤低损耗光谱的一部分。这推动了在铒增益窗口之外工作的放大器的发展。使用固有三阶光学非线性的光参量放大器（OPA）的开创性工作已经证明了信道容量的增加。OPA提供高增益，可以达到保相放大器的3-dB量子极限，并表现出单向操作。然而，高度非线性光纤或体波导的功率要求阻碍了它们的采用。相比之下，基于集成光子电路的OPA具有显著增加模式限制和光学非线性的优点，但带宽有限。

研究组通过在二氧化硅光子集成电路（PIC）上使用低损耗磷化镓克服了这一挑战，并在0.25平方毫米的紧凑占地面积内，用几厘米长的波导实现了高达35dB的参数增益。在约140 nm（即17 THz）的超宽带上实现了超过10 dB的光纤到光纤净增益，与C波段EDFA相比，增益窗口增加了三倍。研究组进一步证明了输入信号的高动态范围，跨越六个数量级，同时保持低噪声系数。利用这些性能特征来放大相干通信信号。据他们所知，这标志着光子芯片中的第一个超宽带、高增益、连续波放大，为下一代集成光子学开辟了新的能力。

附：英文原文

Title: An ultra-broadband photonic-chip-based parametric amplifier

Author: Kuznetsov, Nikolai, Nardi, Alberto, Riemensberger, Johann, Davydova, Alisa, Churaev, Mikhail, Seidler, Paul, Kippenberg, Tobias J.

Issue&Volume: 2025-03-12

Abstract: Optical amplification, crucial for modern communication, primarily relies on erbium-doped fibre amplifiers (EDFAs)1,2. Yet, EDFAs only cover a portion of the low-loss spectrum of optical fibres. This has motivated the development of amplifiers operating beyond the erbium gain window. Pioneering work on optical parametric amplifiers (OPAs)3,4 using intrinsic third-order optical nonlinearity has led to demonstrations of increased channel capacity. OPAs offer high gain, can reach the 3-dB quantum limit for phase-preserving amplifiers and exhibit unidirectional operation. However, power requirements for highly nonlinear fibres3,5,6,7,8 or bulk waveguides9,10 have impeded their adoption. By contrast, OPAs based on integrated photonic circuits offer the advantages of substantially increased mode confinement and optical nonlinearity but have been limited in bandwidth11,12. We overcome this challenge by using low-loss gallium phosphide-on-silicon dioxide13,14,15 photonic integrated circuits (PICs) and attain up to 35dB of parametric gain with waveguides only a few centimetres long in a compact footprint of 0.25square millimetres. Fibre-to-fibre net gain exceeding 10dB across an ultra-broad bandwidth of approximately 140nm (that is, 17THz) is achieved, with a threefold increase in the gain window compared with C-band EDFAs. We further demonstrate a high dynamic range for input signals, spanning six orders of magnitude, while maintaining a low noise figure. We exploit these performance characteristics to amplify coherent communication signals. This marks, to our knowledge, the first ultra-broadband, high-gain, continuous-wave amplification in a photonic chip, opening up new capabilities for next-generation integrated photonics.

DOI: 10.1038/s41586-025-08666-z

Source: https://www.nature.com/articles/s41586-025-08666-z