Optical coupling systems for optically coupling laser diodes to optical fibers

Abstract

Optical coupling systems are provided. An optical coupling system includes a first optical fiber end having a first core, a second optical fiber end having a second core, and a laser diode optically coupled to the first core and the second core at an optical coupling location. The laser diode emits a light beam having an asymmetrical cross-sectional light beam profile comprising a fast axis diameter and a slow axis diameter. The fast axis diameter is longer than the slow axis diameter. Further, the first optical fiber end and the second optical fiber end are adjacently positioned along the fast axis diameter of the asymmetrical cross-sectional light beam profile of the laser diode at the optical coupling location such that the first core and the second core are within the asymmetrical cross-sectional light beam profile at the optical coupling location.

What is claimed is: 
     
         1 . An optical coupling system comprising:
 a first light diffusing optical fiber end;   a second light diffusing optical fiber end;   a laser diode configured to emit a light beam; and   a birefringent crystal disposed between the laser diode and both the first light diffusing optical fiber end and the second light diffusing optical fiber end, wherein the birefringent crystal is configured to split the light beam into a first light beam and a second light beam, direct the first light beam into the first light diffusing optical fiber end, and direct the second light beam into the second light diffusing optical fiber end.   
     
     
         2 . The optical coupling system of  claim 1 , wherein the birefringent crystal comprises an optical axis of about 45°. 
     
     
         3 . The optical coupling system of  claim 1 , wherein the birefringent crystal comprises YVO 4 . 
     
     
         4 . The optical coupling system of  claim 1 , wherein the first light diffusing optical fiber end and the second light diffusing optical fiber end comprise ends of an individual light diffusing optical fiber. 
     
     
         5 . The optical coupling system of  claim 1 , wherein the first light beam comprises an ordinary ray and the second light beam comprises an extraordinary ray. 
     
     
         6 . The optical coupling system of  claim 1 , wherein the first light diffusing optical fiber end comprises a first core, and wherein the birefringent crystal is configured direct the first light beam into the first core. 
     
     
         7 . The optical coupling system of  claim 1 , wherein the second light diffusing optical fiber end comprises a second core, and wherein the birefringent crystal is configured direct the first light beam into the second core. 
     
     
         8 . The optical coupling system of  claim 1 , further comprising one or more focusing lenses positioned between the laser diode and the birefringent crystal. 
     
     
         9 . The optical coupling system of  claim 1 , further comprising one or more focusing lenses positioned between the birefringent crystal and one or both the first optical fiber end and the second optical fiber end. 
     
     
         10 . The optical coupling system of  claim 1 , wherein the birefringent crystal comprise a birefringent material selected from the group consisting of YVO 4 , TiO 2 , LiNBO 3 , and CaCO 3 . 
     
     
         11 . The optical coupling system of  claim 1 , wherein the birefringent crystal comprises an optical axis less than 45°. 
     
     
         12 . The optical coupling system of  claim 1 , wherein the birefringent crystal comprises an optical axis greater than 45°. 
     
     
         13 . The optical coupling system of  claim 1 , wherein the birefringent crystal comprises a propagation angle, wherein the first and second light beam comprise a power component, and wherein the birefringent crystal may be rotated about the propagation angle to alter one of or both of the power component of the first light beam and the second light beam received by the first and second optical fiber ends. 
     
     
         14 . The optical coupling system of  claim 13 , wherein the birefringent crystal may be rotated to a position with respect to the propagation angle such that the first and second light beams comprise equivalent power components. 
     
     
         15 . The optical coupling system of  claim 13 , wherein the birefringent crystal may be rotated to a position with respect to the propagation angle such that the first and second light beams comprise unbalanced power components. 
     
     
         16 . The optical coupling system of  claim 13 , wherein the birefringent crystal may be rotated to a position with respect to the propagation angle such that the first optical fiber end receives a larger or smaller power component than the second optical fiber end. 
     
     
         17 . The optical coupling system of  claim 1 , wherein the birefringent crystal comprises a thickness of about 10 mm thickness and the first light beam and the second light beam are separated by about 1 mm. 
     
     
         18 . The optical coupling system of  claim 1 , wherein the birefringent crystal comprises a thickness of about 2 mm thickness and the first light beam and the second light beam are separated by about 230 μm. 
     
     
         19 . The optical coupling system of  claim 1 , wherein the birefringent crystal comprises a cut angle that changes the spacing between the first light beam and the second light beam. 
     
     
         20 . The optical coupling system of  claim 1 , wherein the laser diode is optically coupled to the first light diffusing optical fiber end and the second light diffusing optical fiber end.