Abstract

Transmission spectra of fiber-optic structures in which transformation of modes occurs in a segment of the thin-core SM450 fiber and a thin-film coating deposited on the cladding are studied. The modes and the corresponding dispersion relations are calculated for the SM450 cladding in the absence and presence of the overlay. It is shown that the dips in the transmission spectrum are caused by interference effects. A setup is constructed for deposition of polyvinyl-alcohol films on a segment of an optical fiber with a length of up to 20 cm with the aid of pulling from solution at a pulling rate of 0.1–1.7 mm/s. Transmission spectra of the structure are measured after deposition of overlays. Spectral shifts result from deposition of thin films. Wavelength shift is determined versus the pulling rate that determines the overlay thickness.

中文翻译：

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基于薄膜覆盖的薄芯光纤的结构光谱

摘要

研究了在纤芯SM450光纤的一部分中发生模态转换的光纤结构的透射光谱，以及在包层上沉积的薄膜涂层。在不存在覆盖层的情况下，计算SM450包层的模式和相应的色散关系。结果表明，传输频谱的下降是由干扰效应引起的。构造了一个装置，用于以0.1–1.7 mm / s的拉速从溶液中拉出，以将聚乙烯醇薄膜沉积在最长20 cm的一段光纤上。在沉积覆盖物之后测量结构的透射光谱。光谱移位是由薄膜沉积引起的。确定波长偏移与确定覆盖层厚度的拉动速率之间的关系。