Cladding Effects on Spectral Transmission of Optical Fibers for Medical Applications

摘要

Key to many laser and sensor applications, in the medical area, is the desire to maintain high core to clad ratios for minimum penetration and maximum flexibility. The transmission of laser beams through optical fibers in a stable, uniform manner is a critical need and assumption for many surgical and sensing medical applications. Cladding thickness has been found to affect the transmission of signals across the electromagnetic spectrum in an uneven manner, especially when typical jacketing materials are used to protect the optical fibers against mechanical/environmental degradation. Experimental data and analysis of the effects of cladding thickness on the spectral transmission of optical fibers having core diameters below 300 μm are presented. Particularly for fibers with below 100 μm core diameters, fibers with cladding/core ratios below 1.2 are shown to have altered transmission spectra at wavelengths above 600 nm. The sensitivity is more pronounced for 'water-free', low-OH optical fibers, which have significant transmission through the near infrared [NIR] region.