An optical coupler includes essentially tubular second connecting piece (40). Second fiber end (14) inserts completely through second connecting piece (40) and is held rigidly such second fiber end (14) is set back from second connecting piece end (78) by a preselected distance. First essentially tubular connecting piece (16) is divided axially into first portion (30) into which first fiber end (12) is inserted and held rigidly, and second portion (32) into which second connecting piece (40) is detachably attached. First and second portions (30, 32) are arranged such that first fiber end (12) is coaxial with and in close proximity to second fiber end (14). Preferably, attachment of second and first connecting pieces (40, 16) includes an axially symmetric groove (46) on an outer surface of second connecting piece (40), and an axially symmetric protrusion (24) on an inner surface of second portion (32) which essentially mates with axially symmetric groove (40).