Abstract: A method of coupling a spliceable optical fibre for transmission of light in its longitudinal direction to an optical component, the method comprising (A) providing the spliceable optical fibre, said spliceable optical fibre comprising: (a) a core region (10, 20, 25, 30, 110); and (b) a microstructured cladding region, said cladding region surrounding said core region and comprising: (b1) an inner cladding region with inner cladding features (13, 22, 112) arranged in an inner cladding background material (11, 21, 111) with a refractive index n1, said inner cladding features comprising thermally collapsible holes or voids, and (b2) an outer cladding region with an outer cladding background material (12, 24, 114) with a refractive index n2; said spliceable optical fibre having at least one end; (B) collapsing said thermally collapsible holes or voids by heating said least one end of said spliceable optical fibre; and (C) coupling said collapsed spliceable optical fibre end to the optical component.