Abstract A wavelength switchable erbium-doped fiber laser was constructed based on an all-fiber Mach–Zehnder interferometer (MZI) comb filter. The MZI consisted of a fiber with two tapers. An L-band erbium-doped fiber was used as the gain medium, and 1557.92, 1563.2, and 1568.06 nm single-wavelength and dual-wavelength switchable lasers at 1558, 1563.7, and 1570.2 nm were realized by adjusting the

Abstract One of the primary challenges in advanced manufacturing (AM) is the lack of efficient optical metrics for ensuring quality control over the manufacturing process. Many current imaging techniques have excessive data requirements and require computationally intensive post-processing to effectively characterize various AM environments. Spatial frequency modulated imaging (SPIFI) addresses many

As the rapid progress in the development of optoelectronic components and computational power, 3D optical metrology becomes more and more popular in manufacturing and quality control due to its flexibility and high speed. However, most of the optical metrology methods are limited to external surfaces. This paper proposed a new approach to measure tiny internal 3D surfaces with a scanning fiber endoscope