| 摘要 |
A directive optical coupler comprises at least two cores (26) of optical guides, made from silica, resting on a sheet of dielectric material (24) and covered by a layer of polymeric material (30) whose refractive index is less than that of the cores. Preferably the coupler is able to function in unimodal manner due to refractive index of polymer; and it is thermo-optically activated by means of an electrode (32) located above the space between the cores, above one of the cores or above both cores and the intervening space. The polymer is a mixture or copolymer of polymers selected from poly(meth)acrylates, alpha -haloacrylates, polystyrenes, polycarbonates, polyvinyls, polyimides and polysiloxanes; and is especially copolymer of trifluoroethylmethacrylate and monomer which can increase refractive index and/or aid crosslinking. |
