Sample Size Determination for Studies with Repeated Continuous Outcomes.

The inventive optical fiber connector comprises a glass ferrule that is strengthened by etching of the outer surface of the ferrule, followed by deposition thereon of a protective layer. Exemplarily, the ferrule is a vitreous silica ferrule drawn from a preform that was made by a sol-gel process. The ferrule is etched in buffered HF, and the protective layer is electroless deposited Ni, with a thin layer of Au thereon. Significant strength increases, exceeding 200%, are obtainable, with the strength being relatively unchanged after even a severe abrasion test.