Abstract: An optical fiber array block includes at least one optical waveguide having an optical fiber zone, and an optical device. An optical signal leakage window is formed at the optical waveguide, and the optical device corresponds to the optical signal leakage window. If the optical signal leakage window is formed at an optical fiber comprising a core and a clad layer, the clad layer is partially removed or is partially connected to the core by means of tan ion implantation technique. Thus, the clad layer has a refractive index that is similar to that of the core.