A coupling bushing 1 for optical fiber connectors comprises a first half structure 1A comprising a base 14 having an axial bore 16 and a socket 15 extending from tlhe rear 21 of the base 14. The socket 15 has a bore 16 axially aligned with the bore of the base 14 to form an extension thereof. The socket 15 is adapted to receive an alignment ferrule of the optical fiber connector. The half structure 1A further comprises, at its front face 20, a pattern of ridges 24 and slots 25 forming keying and aligning feature for intermating with complementary feature of another connecting base. Further, the half structure 1A includes at least one recess 23 and at least one nub 22 forming aligning features for intermating with complementary features of another connecting base. The half structure 1A further comprises a barrel-shaped coupling body 17 extending from the rear face 21 of the base 14 and encompassing the socket 15 within its interior 18. The interior 18 of the coupling body 17, is adapted to receive an end of the optical fiber connector.