Fig. 3: Core surface roughness reduction in HCPCFs.
From: Hollow-core fibers with reduced surface roughness and ultralow loss in the short-wavelength range
a Diagram for the pressure application in the fiber preform during the innovative process proposed in this manuscript; pcore pressure in the fiber core, pclad pressure in the cladding tubes. b Diagram of the interfaces between the surfaces of the cladding tubes, the tubes internal region and the fiber core. c Typical roughness profiles along the fiber axis and d PSD for fibers in G#1 and G#2. e Rms roughness for fibers in G#1 and G#2 (sample numbering according to Table 1). AFM atomic force microscopy, PSD power spectral density.
