Pulse Measurement Techniques for Fiber Optics

题目：两种新型光纤激光脉冲测量技术：测量超弱超短脉冲和时空复杂多空模脉冲非技术描述：本项目将开发两种激光脉冲测量技术，以解决光纤和光纤激光器中两个重要的未解决问题。第一个将解决长期存在的超低能量和相对较长的激光脉冲的超灵敏脉冲测量技术的发展问题。这种脉冲基本上出现在所有的电信环境中，但也出现在许多其他领域。第二种测量技术是针对光纤模式色散问题：不同的空间模式在光纤中以不同的速度传播，因此需要一个完整的时空光测量技术。该技术在单个相机帧上同时生成多种不同颜色的全息图，具有简单、快速和方便的特点。技术描述：目前的脉冲测量技术必须使用一种薄的非线性光学晶体，其输出是强度和晶体厚度的平方，因此产生微弱的输出光束。第一种提出的技术将使用一种非常厚的非线性光学晶体，比其他技术可能的要长得多，以一种新颖的方式产生更高的效率。该晶体还能同时对产生的脉冲进行光谱分解。共线，正交偏振光束和II型晶体也将是必需的。第二种提出的技术同时产生多个全息图，脉冲中的每个波长一个。因为使用单波长光的全息图可以产生光束的完整空间电场，产生许多全息图，每个波长一个，再加上对参考脉冲的完整测量，产生甚至复杂的多模光的完整空间-光谱和时空电场。更棒的是，它只需要一个相机帧就能做到这一点。在未知脉冲和参考脉冲之间使用额外延迟的附加帧可以将范围扩展到任意大的延迟和模式数量。这两种技术都非常便宜、紧凑、实验上易于构建和使用，并且很容易从现成的组件中构建。

Title: Two New Laser Pulse-Measurement Techniques for Fiber Optics: Measuring Ultraweak Ultrashort Pulses and Spatio-Temporally Complex Multi-Spatial-Mode PulsesNon-Technical Description: This project will involve developing two laser pulse-measurement techniques to solve two important unsolved problems in fiber optics and fiber lasers. The first will solve the long-standing problem of the development of an ultrasensitive pulse-measurement technique for very low-energy and relatively long laser pulses-pulses with very low intensities. Such pulses occur in essentially all telecommunications environments, but also in many other fields. The second measurement technique is for the fiber-mode-dispersion problem: different spatial modes propagate at different velocities in a fiber and so require a complete spatiotemporal light-measurement technique. The proposed technique simultaneously generates many different-color holograms on a single camera frame and will also be simple, fast, and convenient.Technical Description: Current pulse-measurement techniques must use a thin nonlinear-optical crystal, whose output scales as the square of the intensity and crystal thickness and so yields a weak output beam. The first proposed technique will instead use a very thick nonlinear-optical crystal, much longer than is possible in other techniques, in a novel manner to yield much higher efficiency. This crystal also simultaneously spectrally resolves the generated pulse. Collinear, orthogonally polarized beams and a Type II crystal will also be required. The second proposed technique generates multiple holograms simultaneously, one for each wavelength in the pulse. Because a hologram using single-wavelength light can yield the complete spatial electric field of a beam, generating many holograms, one for each wavelength, coupled with a complete measurement of the reference pulse, yields the complete spatio-spectral and spatio-temporal electric field of even complex multi-mode light. Even better, it can do so using only a single camera frame. Additional frames using additional delays between the unknown and reference pulses can extend the range to arbitrarily large delays and numbers of modes. Both techniques will be very inexpensive, compact, experimentally simple to build and use, and easily constructed from off-the-shelf components.