GRIN lenses, devices and methods of manufacture

Abstract

Graded index lenses, methods, and devices are disclosed. In certain embodiments, he lenses are made from generally cylindrical glass members having a radially varying refractive index and have a pitch less than about 0.23. Other embodiments relate to graded index lenses having a pitch between about 0.23 and 0.25 and an index gradient less than or equal to 0.3.

What is claimed is:  
     
         1 . A graded index lens comprising a generally cylindrical glass member having a radially varying index of refraction, the glass member having a length such that the lens has a pitch of less than about 0.23.  
     
     
         2 . The graded index lens of  claim 1 , wherein the glass member exhibits a diameter of less than or equal to about 1 mm.  
     
     
         3 . The graded index lens of  claim 2 , wherein the lens is operative to produce a beam having a mode field diameter between about 350 microns and 450 microns when illuminated with a beam having a mode field diameter of about 10.4 microns.  
     
     
         4 . The graded index lens of  claim 1 , wherein the diameter of the lens is between about 1.5 mm and 2 mm.  
     
     
         5 . The graded index lens of  claim 4 , wherein the lens is operative to produce a beam having a mode field diameter exceeding about 500 microns when illuminated with a beam having a mode field diameter of about 10.4 microns.  
     
     
         6 . An optical device including a lens as claimed in  claim 3 .  
     
     
         7 . An optical device including a lens as claimed in  claim 5 .  
     
     
         8 . A method of making a graded index lens comprising obtaining a generally cylindrical glass member having a radially varying index of refraction and forming the glass member having a length such that the lens has a pitch of less than 0.23.  
     
     
         9 . The method of  claim 8 , wherein the diameter of the cylindrical member exhibits a diameter of less than or equal to about 1 mm.  
     
     
         10 . The method of  claim 9 , wherein the lens is operative to produce a beam having a mode field diameter of between about 350 microns and about 450 microns when illuminated with a beam having a mode field diameter of about 10.4 microns.  
     
     
         11 . The method of  claim 8 , wherein the pitch of the lens is between about 0.23 and 0.10.  
     
     
         12 . The method of  claim 9 , wherein the diameter of the cylindrical member is between about 1.5 mm and 2 mm.  
     
     
         13 . The method of  claim 12 , wherein the lens is operative to produce a beam having a mode field diameter exceeding about 500 microns when illuminated with a beam having a mode field diameter of about 10.4 microns.  
     
     
         14 . The method of  claim 12 , wherein the pitch of the lens is between about 0.23 and 0.10.  
     
     
         15 . A collimator comprising an optical fiber and a generally cylindrical graded index lens in a spaced apart relationship, wherein the lens has a pitch less than about 0.23.  
     
     
         16 . The collimator of  claim 15 , wherein for a lens having a diameter of about 1.8 mm and a pitch greater than about 0.10 the working distance between the lens and the fiber is less than about 4 mm.  
     
     
         17 . The collimator of  claim 15 , wherein for a lens having a diameter less than about 1 mm and a pitch greater than about 0.10, the working distance between the fiber and the lens is less than about 2.5 mm.  
     
     
         18 . The collimator of  claim 15 , wherein for a lens having a diameter less than about 0.8 mm and a pitch greater than about 0.10, the working distance between the fiber and the lens is less than about 2.0 mm.  
     
     
         19 . A graded index lens comprising a generally cylindrical glass member having a radially varying index of refraction, a pitch between about 0.23 and 0.25 and an index gradient less than or equal to about 0.3 mm −1 .  
     
     
         20 . The graded index lens of  claim 19 , wherein the diameter of the lens is between about 1.5 and 2.0 mm.