Is the fiber end important?
So far as the actual light output the fiber termination has little affects on the overall light output. However, it is very important; while at the single end will be fixed a few lens system. Imperfections, dig, fractures and scratches at the single end termination will demonstrate as darker patches upon the resulting beam.
The mechanical connection among the single end and the finishing piece, being a board or housing is also dependent upon the actual finish and precision of the single end. Machined pieces, connectors and ferrules have to be scrupulously free of adhesives and with diameters yet, to make sure a precise fitting.