Effects of the damage layer on connection loss of fiber-optic connectors

The damage layer, located at the endface of the fiber-optic connector, is currently the main intrinsic parameter that ultimately limits the connector's ability to achieve the lowest reflectance at the connection point. It deteriorates the connector's return loss and insertion loss and cannot be eliminated by mechanical method. We propose a method called chemical polishing, which is low cost and easy to operate, to eliminate the damage layer. Both theoretical and experimental work have been conducted to reveal the influence mechanism of the damage layer on the return loss and insertion loss. The results show that, by etching the damage layer in a low concentration (≤6%) hydrofluoric acid solution with a short etching time (≤40 s), we can effectively eliminate the damage layer and increase return loss without deteriorating the surface quality.