System and method for integrating optical layers in a PCB for inter-board communications

Abstract

Polymers of differing refraction indices are embedded within a PCB to provide optical connectivity of the PCB with other circuit boards via an optic backplane. The creation of islands of polymer material of refractive index n1 completely surrounded by polymer material with refractive index n2 where n1 has a higher index than n2 allows the islands of n1 indexed polymer to serve as optical waveguides. A process of forming a multi-layered PCB with the optical waveguide islands using successive laminations and using laser ablation to write the optical connection scheme is taught. Further, the use of uniquely marked targets in a copper layer to align the optical waveguides in production is also taught. Additionally, the use of clearing polymer materials and reinforcing polymer voids with lamination to allow a simple, high tolerance insertion of through-holes is taught.

1 . A method for making an optical transmitting material capable of being integrated with a printed circuit board, the method comprising: 
 applying onto a layer of a first material a layer of a second material having a refraction index greater than a refraction index of the first material;    creating a channel through the layer of second material;    filling the channel and covering the remaining layer of second material with a third material having a refraction index less than the refraction index of the second material such that the remaining portion of the layer of second material forms at least one optical waveguide.    
   
   
       2 . An optical transmitting material capable of being integrated with a printed circuit board comprising: 
 a layer of a first material;    a layer of a second material applied to the layer of first material, wherein the layer of second material has a channel formed through the layer of second material and wherein the second material has a refraction index greater than the refraction index of the first material; and    a layer of third material applied to the layer of second material, wherein the third material has a refraction index less than the refraction index of the second material and wherein the layer of third material covers the layer of second material and fills the channel such that the layer of second material forms at least one optical waveguide.