a light - wave conductor cable is described within the core of which there is at least one ribbon line in which light - wave conductors are arranged alongside of and parallel to each other . the light - wave conductors are enclosed between two ribbons the material of which has the same coefficient of thermal expansion as the light - wave conductors . the ribbons consist preferably of fiberglass - reinforced plastic . the ribbon line may be disposed within an outer jacket , and therein arranged straight or curved or , in the case of several ribbon lines , in ordered or random fashion and about a core of the light - wave conductor cable .