Unitary Fourier transform lies at the core of the multitudinous computational and metrological algorithms. Here we show experimentally how the unitary Fourier transform-based phase estimation protocol, used namely in quantum metrology, can be translated into the classical linear optical framework. The developed setup made of beam splitters, mirrors and phase shifters demonstrates how the classical coherence, similarly to the quantum coherence, poses a resource for obtaining information about the measurable physical quantities. Our study opens route to the reliable implementation of the small-scale unitary algorithms on path-encoded qudits, thus establishing an easily accessible platform for unitary computation.

ary傅里叶变换是众多计算和计量算法的核心。在这里，我们通过实验展示了如何在量子计量学中使用的基于单一傅立叶变换的相位估计协议可以转换为经典的线性光学框架。由分束器，反射镜和移相器组成的已开发装置展示了经典相干性（与量子相干性相似）如何构成获取有关可测物理量信息的资源。我们的研究为在路径编码的qudits上可靠地实现小规模unit算法开辟了道路，从而建立了易于访问的unit计算平台。