RIA: Spatial Coherence for Determining Mode Structure in Optoelectronic Devices

虽然一般不可能观察到 直接计算了光场分布 波导器件，一种获得 信息是检查空间相干性 发射光束的SCF函数。 很少 信息已公布的空间 光电子器件的相干性， 通常测量的繁琐性质 技术（即杨氏双缝），和相对 这些装置中的低光功率。 一种新的纤维- 的干涉技术已经发展起来 由首席研究员，这是第一次 允许直接和可重复的测量 低功率光束的空间相干性。 本研究启动奖计划使用 测量SCF以确定模式 在激光二极管的腔中的分布。 三 提出了可能的方法：1）非严格的 一阶分析的基础上调用货车Cittert- Zernike定理（不严格适用于相干 光源，如激光，但相干效应可以是 （2）时间平均法;（3） Spano的，即写下表达式的 光学腔中的前几个模式，并预测 SCF，然后使用测量的SCF提取 每个模式的权重;以及3）调整算法 Tervonen等人，他提出了一种方法， 从SCF计算模式分布， 厄米-高斯模式（光纤），平面 例如用于激光二极管的波导， 光电集成电路

Although it is not generally possible to observe directly the optical field distribution in optical waveguiding devices, one approach to obtaining the information is to examine the spatial coherence function (SCF) of the emitted beam. Very little information has been published on the spatial coherence of optoelectronic devices due to the cumbersome nature of the usual measurement technique (i.e. Young's double slit), and the relatively low optical powers in these devices. A new fiber- based interferometric technique has been developed by the principal investigator, which, for the first time, allows the direct and repeatable measurement of spatial coherence of low-power light beams. It is planned in this Research Initiation Award to use the measured SCF to determine the mode distribution in the cavities of laser diodes. Three possible approaches are proposed: 1) a non-rigorous first order analysis based on invoking the Van Cittert- Zernike Theorem (not strictly applicable to coherent sources such as lasers, but coherence effects can be removed by time-averaging); 2) an approach following that of Spano, i.e. writing down expressions for the first few modes in an optical cavity and predicting the SCF, then using the measured SCF to extract the weight for each mode; and 3) adapting the algorithm of Tervonen et al, who presents a method for computing the mode distribution from the SCF for Hermite-Gaussian modes (fiber), to planar waveguides such as those used in laser diodes and optoelectronic integrated circuits.