their optical cores are brought sufficiently close together to allow evanescent field optical coupling from one to the other fig5 which is a cross sectional view taken transversely of housing 116 illustrates the optical fibers disposed adjacent a face of support ribbon fiber 114 for purposes of illustration the optical fibers and ribbon fiber in fig5 are shown greatly enlarged in relation to housing 116 in the actual coupler as manufactured the housing may be as much as 1 2 cm in diameter while the width of ribbon fiber 114 is only around 400 800 microns a glue or soft setting resin material is applied over a portion of the ribbon face to cover the optical fibers this material is selected to set to a resilient consistency to define a soft encapsulant 136 surrounding the fibers the encapsulant may be applied on only one side of the ribbon fiber as illustrated in fig5 or it may be applied to encircle the ribbon fiber completely after encapsulant 136 is cured another glue or epoxy material selected to set to a hard consistency is introduced into the remaining space in the housing chamber and allowed to solidify to define hard encapsulant 132 which completely surrounds soft encapsulant 136 and ribbon fiber 114 an alternate arrangement for encapsulanting the optical fibers is illustrated in fig6 optical fibers 212 and 212 39 are surrounded by a soft encapsulant 236 with spaced ribbon fibers 214 and 214 39 having either flat or longitudinally recessed facing surfaces disposed on opposite sides thereof a material selected to set to.