Structures that correct for thermal distortion in an optical device formed of thermally dissimilar materials

Abstract

Numerous novel structures and methods are presented for their ability to correct angular and offset alignment errors caused by thermal distortion of a device formed out of dissimilar materials, such as a movable platform and waveguide coupled to a fixed platform and another waveguide. A flexure connected between two platforms corrects offset alignment errors along the centerline axis of the flexure. Thermal distortion is corrected also by varying the relative size of the two platforms and the addition of slots and/or extraneous waveguides. A waveguide may be sandwiched between two matching materials, with or without an extra thermal compensation layer portion. A method uses simple processes to build a substrate with matching waveguides on each side of the substrate. Another simple method creates a suspended structure by using simple semiconductor processes.

1 . An optical device comprising: 
 a fixed structure;    a movable structure to move relative to the fixed structure and being disposed adjacent to the fixed structure;    a first light guiding structure mounted on the fixed structure, the first light guiding structure comprising a different material than the fixed structure;    a second light guiding structure mounted on the movable structure, the second light guiding structure comprising a different material than the movable structure, each of the first and second light guiding structures having an end such that the ends of the first and second light guiding structures are aligned to propagate an optical signal between the first and second light guiding structures; and    a flexure having a first end coupled to the movable structure and a second end coupled to the fixed structure, the flexure having a first point that remains in zero or near-zero translation, the ends of the first and second light guiding structures being positioned at or near the first point of the flexure.    
     
     
         2 . The optical device of  claim 1  wherein the first point is at the centerline halfway between the first and second ends of the flexure.  
     
     
         3 . The optical device of  claim 1  wherein the first point is located a distance from the centerline halfway between the first and second ends of the flexure.  
     
     
         4 . The optical device of  claim 1  wherein the first light guiding structure is a waveguide.  
     
     
         5 . The optical device of  claim 1  wherein the second light guiding structure is a waveguide.  
     
     
         6 . The optical device of  claim 4  wherein the second light guiding structure is a waveguide.  
     
     
         7 . The optical device of  claim 2  further comprising a second flexure having a first end coupled to the movable structure and a second end coupled to the fixed structure, the second flexure having a centerline halfway between the first and second ends of the flexure, the ends of the first and second light guiding structures being positioned at or near the centerline of the second flexure.  
     
     
         8 . The optical device of  claim 1  wherein the ends of the first and second light guiding structures are positioned at substantially equal distance from the first point of the flexure.  
     
     
         9 . The optical device of  claim 7  wherein the ends of the first and second light guiding structures are positioned at substantially equal distance from the first point of the second flexure.  
     
     
         10 . The optical device of  claim 1  wherein the flexure has a first bend and a second bend, the first and second bends being located on opposite sides of the first point.  
     
     
         11 . The optical device of  claim 10  wherein the flexure has a third bend and a fourth bend, the third and fourth bends being located on opposite sides of the first point.  
     
     
         12 . The optical device of  claim 3  further comprising a second flexure having a first end coupled to the movable structure and a second end coupled to the fixed structure, the second flexure having a second point that remains in zero or near-zero translation, the ends of the first and second light guiding structures being positioned at or near the second point of the second flexure.  
     
     
         13 . The optical device of  claim 8  wherein the first point is at the centerline halfway between the first and second ends of the flexure.  
     
     
         14 . The optical device of  claim 9  wherein the first point is at the centerline halfway between the first and second ends of the flexure.  
     
     
         15 . The optical device of  claim 1  wherein the flexure has a first bend and a second bend, the first and second bends being located on opposite sides of the first point, the first point being at the centerline halfway between the first and second ends of the flexure.