Novel photonic devices based on the concept of space-time duality

非技术性描述本项目探索光纤内光脉冲的相互作用。具体来说，强光脉冲可以改变玻璃纤维的光学特性，如折射率。 就像空气和一块窗户玻璃之间折射率的变化会导致一些入射光被反射一样，强烈的光脉冲引起的折射率变化也会改变光的传播。这种变化是短暂的，并在光纤中以光速传播。如果两个不同频率的光脉冲在光纤中传播，它们将以不同的速度传播。如果其中一个脉冲的强度足以改变光纤的材料特性，第二个脉冲将分裂成两个新频率的两个脉冲。全内反射的时间形式也可以发生，使得整个脉冲能量永远不会穿过时间边界，在该时间边界上折射率改变其数值。这些现象已经被预测，但尚未被观察到。观察这些相互作用将使一类新的光子器件成为可能，其中光由光控制。这项研究将进一步推进我们对超快光学领域的理解，并为脉冲操纵和整形提供新的工具。这样的设备很可能会发现应用在各种技术领域，从电信到生物医学engineering.Technical Description的概念的空间-时间的二重性将使我们能够应用已知的技术从空间衍射的光束控制短脉冲在时域。拟议的研究将通过深思熟虑的实验开发新型光子器件，这些实验将由PI近年来开发的理论和数值专业知识指导。最初的实验将利用光纤内部交叉相位调制的非线性现象实现时间波导。由此产生的波导将用于控制由独立运行的锁模激光器发射的两个脉冲序列之间的定时抖动。 另一个目标是使用电光相位调制器合成任意形状的脉冲。由于我们的方法主要基于相位变化，因此与替代方案相比，它预计具有更低的插入损耗，并且适用于能效是最高要求的应用。我们还将采用时间形式的塔尔博特效应，将连续波信号转换成重复率可调的光脉冲源。在这个项目中，我们将与研究生和本科生合作，充分探索时空二重性的含义，并开发具有超快科学和技术领域功能和应用的新型光子器件。这个奖项反映了NSF的法定使命，并通过使用基金会的智力价值和更广泛的影响审查标准进行评估，被认为值得支持。

Nontechnical Description This project explores the interaction of light pulses inside optical fibers. Specifically, intense light pulses can change the optical properties, like the index of refraction, of a glass fiber. Just as the change in the index of refraction between air and a piece of window glass causes some of the incident light to be reflected, the index of refraction change caused by an intense optical pulse can also alter the propagation of light. This change is transient and propagates at the speed of light in the fiber. If two light pulses of different frequencies propagate in an optical fiber, they will travel at different velocities. If one of those pulses is intense enough to change the material properties of the fiber, the second pulse will split into two pulses at two new frequencies. A temporal version of total internal reflection can also occur such that the entire pulse energy never crosses the temporal boundary across which the index of refraction changes its numerical value. These phenomena have been predicted but have not yet been observed. Observing these interactions will enable a new class of photonic devices where light is controlled by light. The proposed research will further advance our understanding in the field of ultrafast optics and provide us new tools for pulse manipulation and shaping. Such devices are likely to find applications in a variety of technical areas ranging from telecommunications to biomedical engineering.Technical Description The concept of space-time duality will allow us to apply the techniques known from spatial diffraction of optical beams to control short pulses in the time domain. The proposed research will develop novel photonic devices through well-thought experiments that will be guided by the theoretical and numerical expertise the PIs have developed in recent years. The initial experiments will realize a temporal waveguide using the nonlinear phenomena of cross-phase modulation inside an optical fiber. The resulting waveguide will be used to control timing jitter between two pulse trains emitted by independently running mode-locked lasers. Another objective is to synthesize pulses of arbitrary shapes using an electro-optic phase modulator. Since our approach is based mostly on phase changes, it is expected to have lower insertion losses compared to alternatives and would be suitable for applications where energy efficiency is a top requirement. We shall also employ the temporal version of the Talbot effect to convert a continuous-wave signal into a source of optical pulses whose repetition rate is tunable. In this project, we will work with graduate and undergraduate students to explore fully the implications of space-time duality and develop novel photonic devices with functionalities and applications in the areas of ultrafast science and technology.This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.