Rare earth doped optical glasses

Abstract

A glass component in an optical system, which may be a lazing or an optical amplifying medium, comprising a silicate base glass doped with at least two Group III B elements, the glass, and a method of preventing clustering of a rare earth metal ion in the glass.

We claim:  
     
         1 . A glass component in an optical system comprising a silicate base glass doped with at least two oxides of Group III B elements, at least one of the elements being a rare earth.  
     
     
         2 . A glass component in accordance with  claim 1  in which the silicate base glass is doped with erbium.  
     
     
         3 . A glass component in accordance with  claim 2  in which the silicate base glass contains, as the second dopant, an oxide of an element selected from yttrium, gadolinium and lanthanum.  
     
     
         4 . A glass component in accordance with  claim 1  in which the base glass is an alkali metal silicate glass.  
     
     
         5 . A glass component in accordance with  claim 1  in which the base glass is an alumino silicate glass.  
     
     
         6 . A glass component in accordance with  claim 1  in which the base glass is a fluorinated silicate glass having a fluorine content of at least 4.5% by weight.  
     
     
         7 . A glass component in accordance with  claim 1  in which the glass is a component of a laser or an optical amplifier.  
     
     
         8 . A glass component in accordance with  claim 1  in which the component is an optical signal carrier.  
     
     
         9 . A glass component in accordance with  claim 8  in which the component is a clad, optical waveguide fiber.  
     
     
         10 . A glass component in accordance with  claim 8  in which the component is a planar optical amplifier, or a fiber optical amplifier.  
     
     
         11 . A method of decreasing clustering of a rare earth element in a silicate glass which comprises including in the glass composition at least one additional Group III B element.  
     
     
         12 . A method in accordance with  claim 11  wherein the rare earth element subject to clustering is erbium.  
     
     
         13 . A method in accordance with  claim 11  wherein the additional Group III B element is yttrium, gadolinium or lanthanum.  
     
     
         14 . A method in accordance with  claim 11  wherein the silicate glass is an alumina silicate glass.  
     
     
         15 . A method in accordance with  claim 11  wherein the silicate glass is a fluorinated silicate glass.  
     
     
         16 . A method in accordance with  claim 11  which comprises forming an optical fiber core by delivering the precursors of at least two different Group III B element oxides, and the precursor of an oxide glass former, to an oxy-gas burner to form an oxide mixture, and depositing the mixture on a mandrel to form a preform for the core.  
     
     
         17 . A method in accordance with  claim 16  which further comprises depositing a cladding oxide layer on the preform, and drawing a fiber from the clad core.  
     
     
         18 . A silicate glass containing in its composition at least two different Group III B elements.  
     
     
         19 . A silicate glass in accordance with  claim 18  in which one of the two Group III B elements is erbium.  
     
     
         20 . A silicate glass in accordance with  claim 19  in which a second Group III B element is yttrium, gadolinium or lanthanum.  
     
     
         21 . An alkali silicate glass in accordance with  claim 18  in which the composition includes 5-30% of at least one alkali metal oxide.  
     
     
         22 . An alkali silicate glass in accordance with  claim 21  wherein the alkali metal oxide is soda, potassia or mixtures thereof.  
     
     
         23 . An alumino silicate glass in accordance with  claim 18  in which the composition includes 5-20 mole % Al 2 O 3 .  
     
     
         24 . A fluorinated silicate glass in accordance with  claim 18  in which the composition includes at least 4.5% fluorine.  
     
     
         25 . An silicate glass in accordance with  claim 18  consisting essentially of, in addition to the two Group III B elements, as calculated from the glass batch on an oxide basis in mole %,  
       
         
           
                 
                 
                 
               
                     
                     
                 
                     
                     
                 
                     
                   SiO 2   
                   55-80% 
                 
                     
                   Na 2 O 
                    0-30% 
                 
                     
                   K 2 O 
                    0-30% 
                 
                     
                   Na 2 O + K 2 O 
                    5-30% 
                 
                     
                   Al 2 O 3   
                    0-20% 
                 
                     
                   F 
                    0-13% (by wt).