In an optical waveguide tube comprising a tubular cladding (2) filled with a solid core (3) having a higher refractive index than the cladding, a ferrule (6) surrounding the outer periphery of the cladding at each end is fastened for securing the cladding to the core at each end for preventing the core from projecting out of the cladding. The ferrule may have a collar disposed in abutment with the core end face.
