substrate portions 21 and 22 the 39 174 patent provides for machine placement of opposite optical fiber support elements of the type shown in fig2 machine placement of the support members is greatly facilitated by making them of plastic rather than silicon in particular injection molding is used to make the opposite segments which is a much less expensive process than masking and etching and allows the formation of structural features such as angle steps needed for precise alignment and placement as illustrated in fig4 the first step in this procedure is to make an array of v grooves 25 in a monocrystalline body 26 such as silicon by the conventional masking and etching process this defines the v grooves with the requisite precision however to allow for shrinkage of the plastic during the subsequent molding process the v grooves should be made somewhat larger than is finally intended for the final optical fiber support a metal layer 27 is then electroformed over the v grooves thereafter the silicon body 26 is removed or destroyed as by etching it in for example a mixture of hf hno3 and water or koh and water other known etchants of silicon could alternatively be used the metal layer 27 is then used as an insert in a mold which defines the remaining configuration of the support members that is fiber support members are made by injection molding using a mold having the metal layer insert in the portion of the mold defining the v grooves.