Layered optical circuit

Abstract

A layered optical circuit including a multi-substrate optical circuit. The multi-substrate optical circuit includes a plurality of optical fibers, a first substrate supporting a first portion the optical fibers to form a first optical subcircuit, and a second substrate supporting a second portion of the optical fibers to form a second optical subcircuit. A third portion of the optical fibers between the first and second portions extends between the first and second substrates. Free fibers in the third portion are elongated to permit repositioning of the first and second optical subcircuits in an overlapping arrangement without exceeding a minimum bend radius of each of the optical fibers. The overlapping arrangement of the first and second optical subcircuits forms a layered optical circuit. Accordingly, a layered optical circuit having a large number of fibers and/or a complex circuit pattern may be affixed on a relatively small footprint of a backplane, etc.

1. A multi-substrate optical circuit for forming a layered optical circuit, the multi-substrate optical circuit comprising:
 a plurality of optical fibers, each having a first, second and third portion;  
 a first substrate supporting said first portions of said plurality of optical fibers to form a first optical subcircuit; and  
 a second substrate supporting said second portions of said plurality of optical fibers to form a second optical subcircuit;  
 wherein said third portions of said plurality of optical fibers connects said first and second portions and comprise free fibers having sufficient length to ensure at least a minimum bend radius of said plurality of optical fibers.  
 
   
   
     2. A layered optical circuit comprising:
 a plurality of optical fibers, each having a first, second and third portion;  
 a first substrate supporting said first portions of said plurality of optical fibers to form a first optical subcircuit; and  
 a second substrate supporting said second portions of said plurality of optical fibers to form a second optical subcircuit, said respective second portion being longitudinally spaced from said respective first portion along each of said plurality of optical fibers;  
 wherein said second substrate is positioned to at least partially overlap said first substrate.  
 
   
   
     3. The layered optical circuit of  claim 2 , wherein said second substrate entirely overlaps said first substrate. 
   
   
     4. The layered optical circuit of  claim 2 , wherein each said third portion connects respective first and second portions, said third portion having sufficient length to ensure at least a minimum bend radius between said respective first and second portions. 
   
   
     5. The layered optical circuit of  claim 2 , wherein each of said first and second substrates has a front side to which said plurality of optical fibers is affixed, and a back side opposite said front side, and wherein said front side of said second substrate is positioned facing said front side of said first substrate. 
   
   
     6. The layered optical circuit of  claim 2 , wherein each of said first and second substrates has a front side to which said plurality of optical fibers is affixed, and a back side opposite said front side, and wherein said front side of said second substrate is positioned facing said back side of said first substrate. 
   
   
     7. The layered optical circuit of  claim 2 , wherein said second substrate is mounted in fixed position to said first substrate. 
   
   
     8. The layered optical circuit of  claim 2 , wherein at least one of said plurality of optical fibers has a first end extending beyond an edge of said first substrate, and a second end extending beyond another edge of said second substrate. 
   
   
     9. The layered optical circuit of  claim 8 , wherein each of said first and second ends of said plurality of optical fibers is terminated to a fiber optic connector. 
   
   
     10. The layered optical circuit of  claim 8 , wherein said second substrate is bonded to said first substrate. 
   
   
     11. The layered optical circuit of  claim 8 , wherein said second substrate is mechanically fastened to said first substrate. 
   
   
     12. The layered optical circuit of  claim 8 , wherein said second substrate and said first substrate are affixed to a carrier. 
   
   
     13. A method for fabricating a layered optical circuit, the method comprising:
 providing a first substrate;  
 providing a second substrate in spaced relationship to said first substrate, said first and second substrates being positioned in substantially the same plane;  
 affixing to said first substrate a first portion of a plurality of optical fibers;  
 affixing to said second substrate a second portion of said plurality of optical fibers, said second portion being longitudinally spaced from said first portion; and  
 positioning at least a portion of said second substrate to overlap said first substrate, said portion being displaced from the plane of said first substrate.  
 
   
   
     14. The method of  claim 13 , wherein positioning at least a portion of said second substrate comprises a planar rotation of said second substrate. 
   
   
     15. The method of  claim 13 , wherein positioning at least a portion of said second substrate comprises a planar translation of said second substrate. 
   
   
     16. The method of  claim 13 , further comprising:
 mounting said second substrate in fixed position to said first substrate.  
 
   
   
     17. The method of  claim 13 , wherein positioning at least a portion of said second substrate comprises an inversion of said second substrate. 
   
   
     18. The method of  claim 17 , wherein mounting to said second substrate a second portion of each of said plurality of optical fibers comprises twisting said plurality of optical fibers in a transition area defined between said first and second portions of said plurality of optical fibers, whereby the inversion of said second substrate untwists said plurality of optical fibers. 
   
   
     19. A method for fabricating a multi-substrate optical circuit, the method comprising:
 providing a first substrate;  
 providing a second substrate in substantially the same plane as said first substrate;  
 mounting to said first substrate a first portion of each of a plurality of optical fibers; and  
 mounting to said second substrate a second portion of each of said plurality of optical fibers, said second portion being longitudinally spaced from said first portion by a third portion of each of said plurality of optical fibers, said third portion having a length for overlapping said first and second substrates without exceeding a minimum bend radius of each of said plurality of optical fibers within said third portion.  
 
   
   
     20. The method of  claim 19 , wherein providing said second substrate comprises positioning said second substrate at a distance from said first substrate to provide the length between adjacent edges of said first and second substrates. 
   
   
     21. A multi-substrate optical circuit for forming a layered optical circuit, the multi-substrate optical circuit comprising:
 a first optical subcircuit comprising a plurality of optical fibers supported on a first substrate in a first circuit pattern, a first end of each of said plurality of optical fibers extending beyond an edge of said first substrate to provide a first termination leg; and  
 a second optical subcircuit comprising said plurality of optical fibers supported on a second substrate in a second circuit pattern, a second end of each of said plurality of optical fibers extending beyond a respective edge of said second substrate to provide a second termination leg, said first plurality of optical fibers providing a continuous communication path between respective first and second termination legs and across said first and second substrates.  
 
   
   
     22. The multi-substrate optical circuit of  claim 21 , wherein said continuous communication path has a length between said edge of said first substrate and said respective edge of said second substrate permitting at least partial overlapping of said first and second optical subcircuits without exceeding a minimum bend radius of said plurality of optical fibers.