A connector of a bundle of optical fibers comprises a ferrule including an axial lower channel for receiving the bundle of optical fibers, and an axial upper tunnel in communication with the channel, and a rigid, cylindrical sheath received in the tunnel and including a bore for receiving the bundle, an aperture through a closed end of the sheath, and an annular neck. Inserting the bundle into the channel and the tunnel until being stopped with strands of optical fiber passed the aperture, and then pressing the sheath will break the sheath at the neck and compress the neck inwardly into the sheath to form a narrow section around the bundle for fastening. An additional base is provided in another embodiment.