頻率解析光閘(frequency-resolved optical gating, or FROG)為一廣泛使用之超短光脈衝量測方法。實驗上，FROG使用非同軸(noncollinear)麥克森干涉儀(Michelson interferometer)擷取頻譜圖(spectrogram)，再依賴疊代演算法(iterative algorithm)找出待測脈衝的複數電場包絡(complex field envelope)函數。當改用同軸(collinear)麥克森干涉儀時，會得到包含干涉條紋及背景訊號的干涉頻譜圖(interferometric spectrogram)。本論文主要以實驗探討如何使用單一之干涉頻譜圖及兩種不同的數據分析方法：（一）FROG，（二）修正干涉場自相關(modified interferometric field autocorrelation, or MIFA)，分別可求出待測脈衝的複數電場包絡函數或相位頻譜(spectral phase)函數。此外並深入探討藉由多重取樣平均提升MIFA測量法對雜訊的抵抗能力。並介紹現今三種脈衝測量法之功能及優缺點比較如下：
一、FROG：可以同時得到功率頻譜及相位頻譜函數，但是需要用到光譜儀擷取二維資料並進行疊代分析。
二、MEFISTO：可以得到相位頻譜函數，但亦須使用到光譜儀擷取二維資料，其中時間延遲軸的解析度(delay resolution)需能解析出稠密之干涉條紋(資料量極大)。最後利用代數遞迴關係式還原資訊。
三、MIFA：可以得到相位頻譜函數，只需使用到單點光源偵測器擷取一維資料，再利用代數遞迴關係式還原資訊。
詳細實驗架構與原理詳見章節2.1到章節2.3。

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