Optical parametric amplification is one of the most flexible approaches for generating coherent light at long wavelengths, but typical implementations require prohibitively large pump pulse energies to realize useful amounts of gain. In this work, we experimentally demonstrate an approach to optical parametric amplification in which an interplay between parametric gain and symmetric temporal walk-off confines the non-degenerate signal and idler to form a three-wave soliton. Gain-trapped solitons propagate stably over arbitrarily long interaction lengths, which reduces the energy required for high-gain operation by orders of magnitude. The devices demonstrated here realize large parametric gains ({\gt}70\;{\rm dB} ${\gt}70\;{\rm dB}$) with only picojoules of pump pulse energy in a 5-mm-long thin-film lithium niobate on sapphire nanowaveguide. In addition, we observe an array of desirable features including high conversion efficiencies ({\gt}50\%${\gt}50\%$), wide tuning ranges ({\gt}100\;{\rm nm} ${\gt}100\;{\rm nm}$), and broad spectral bandwidths ({\gt}180\;{\rm nm} ${\gt}180\;{\rm nm}$ 3 dB for the 3200-nm idler). When combined with the dispersion engineering available in tightly confining nanowaveguides, this approach enables high-gain optical parametric amplifiers operating at any wavelength.

中文翻译：

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通过增益捕获孤子进行高效参数下变频

光学参量放大是产生长波长相干光的最灵活的方法之一，但典型的实现需要非常大的泵浦脉冲能量才能实现有用的增益量。在这项工作中，我们通过实验演示了一种光学参量放大方法，其中参量增益和对称时间走离之间的相互作用限制了非简并信号和闲频信号以形成三波孤子。增益捕获孤子在任意长的相互作用长度上稳定传播，这将高增益操作所需的能量减少了几个数量级。这里演示的器件在蓝宝石纳米波导上的 5 毫米长薄膜铌酸锂中仅用皮焦耳的泵浦脉冲能量即可实现大参数增益 ( {\gt}70\;{\rm dB})${\gt}70\;{\rm dB}$ 。此外，我们观察到一系列理想的特性，包括高转换效率（{\gt}50\%${\gt}50\%$）、宽调谐范围（{\gt}100\;{\rm nm}${\gt}100\;{\rm nm}$）和宽光谱带宽（{\gt} }180\;{\rm nm}${\gt}180\;{\rm nm}$ 3 dB（对于 3200 nm 惰频）。当与紧密限制的纳米波导中可用的色散工程相结合时，这种方法可以实现在任何波长下工作的高增益光参量放大器。