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In the field of optical communication, either fusion splicing of optical fibers or physical contact between optical-fibers
using a fiber connector has been utilized as the typical method of optical fiber connection. Optical fiber connectors have
been widely employed in optical transmission systems according to their features of easy and quick connection without
special apparatus to connect fibers. The power of laser diodes for light sources became more intense and the
multiplexing of wavelength (WDM) of a light source was enhanced with increasing traffic data. As a result, intense light
transmits through the optical fiber. The high power transmission characteristics of the optical fiber connector are
important factors to realize dense wavelength division multiplexing systems (DWDM).
In this paper, we present an experimental investigation about the degradation of the transmission properties through the
optical fiber connector by introducing the contamination between the end faces of a connector. The metal foils to
simulate the contamination at the end of the core were inserted between the optical fibers to cover the core of an optical
fiber partially. As metal foils, Nickel, SUS304, and Phosphor Bronze which were typically used as the components of
the ferrule and sleeve were selected. The Nd: YAG laser with the wavelength of 1064 nm was used as a high power light
source at various output powers. The transmission loss was set by adjusting the insertion of a metal foil into the core
region of the fiber and the temperature rising of the connector induced by the absorption of incident light was measured
at a sleeve portion. The damage at the end face of the physical contact region was observed using an optical microscope.
The temperatures increase of the core of the fiber was estimated for the fiber connector with a zirconia ferrule through
the thermal simulation using the MSC Visual Nastran.
The damage of the fiber end face was recognized depending on the species of the metal foil and the covering ratio for
the core in the case of a high power light transmission, typically, with the average power of 1W. It was estimated that
the damage threshold of the fiber end becomes low for the ferrule with lower melting point. The correlation between the
damage threshold and various parameters was discussed.
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