Complete temporal mode analysis in pulse-pumped fiber-optical parametric amplifier for continuous variable entanglement generation.
Complete temporal mode analysis in pulse-pumped fiber-optical parametric amplifier for continuous variable entanglement generation.
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DOI：
10.1364/oe.23.029369
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发表时间：
2015-11
期刊：
影响因子：
3.8
通讯作者：
Xueshi Guo;Nannan Liu;Xiaoying Li;Z. Ou
中科院分区：
文献类型：
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作者：
Xueshi Guo;Nannan Liu;Xiaoying Li;Z. Ou
模匹配在测量连续变量纠缠中起着重要的作用。对于脉冲泵浦光纤参量放大器(FOPA)产生的信号和闲置双光束，在单模光纤中可以自动实现空间模匹配，但由于其对FOPA的色散和增益高度敏感，时间模特性较为复杂。利用奇异值分解方法对双光束的联合谱函数进行分解，研究了信号光束和闲置光束的时间模结构，导出了信号和闲置光束各时间模的输入输出关系。对正交幅度纠缠的测量进行了分析，发现多模双光束与零差探测系统的本征振荡器之间的模式匹配是实现高度纠缠的关键。结果表明，与本机振荡器非正交的时间模所贡献的噪声可能比真空噪声大得多，因此不能仅仅通过引入有效损耗来解释模式失配。我们的研究将有助于利用FOPA开发高质量的连续变量纠缠源。
Mode matching plays an important role in measuring the continuous variable entanglement. For the signal and idler twin beams generated by a pulse pumped fiber optical parametric amplifier (FOPA), the spatial mode matching is automatically achieved in single mode fiber, but the temporal mode property is complicated because it is highly sensitive to the dispersion and the gain of the FOPA. We study the temporal mode structure and derive the input-output relation for each temporal mode of signal and idler beams after decomposing the joint spectral function of twin beams with the singular-value decomposition method. We analyze the measurement of the quadrature-amplitude entanglement, and find mode matching between the multi-mode twin beams and the local oscillators of homodyne detection systems is crucial to achieve a high degree of entanglement. The results show that the noise contributed by the temporal modes nonorthogonal to local oscillator may be much larger than the vacuum noise, so the mode mis-match can not be accounted for by merely introducing an effective loss. Our study will be useful for developing a source of high quality continuous variable entanglement by using the FOPA.