Fiber-based output couplers for wavelength beam combining laser systems

Abstract

In various embodiments, wavelength beam combining laser systems incorporate optical fibers and partially reflective output couplers or partially reflective interfaces or surfaces utilized to establish external lasing cavities.

What is claimed is: 
     
         1 .- 24 . (canceled) 
     
     
         25 . A method of forming an optical beam, the method comprising:
 emitting a plurality of input beams with a plurality of beam emitters;   forming an external laser cavity between the beam emitters and a partially reflective component disposed within or on an optical fiber, whereby the external laser cavity stabilizes each of the input beams at a different wavelength;   combining the plurality of input beams to form a multi-wavelength output beam; and   emitting at least a portion of the multi-wavelength output beam.   
     
     
         26 . The method of  claim 25 , wherein the multi-wavelength output beam is emitted from the optical fiber. 
     
     
         27 . The method of  claim 25 , further comprising delivering the multi-wavelength output beam to a workpiece for processing thereof. 
     
     
         28 . The method of  claim 27 , wherein processing the workpiece comprises at least one of cutting or welding. 
     
     
         29 . The method of  claim 25 , further comprising rotating at least one of the input beams before the input beams are combined. 
     
     
         30 . The method of  claim 25 , further comprising collimating at least one of the input beams. 
     
     
         31 . The method of  claim 25 , wherein the partially reflective component comprises a fiber Bragg grating. 
     
     
         32 . The method of  claim 31 , wherein (i) the optical fiber comprises one or more cores at least partially surrounded by one or more cladding layers, and (ii) at least a portion of the fiber Bragg grating is disposed within at least one core of the optical fiber. 
     
     
         33 . The method of  claim 25 , wherein the partially reflective component comprises an interface between the optical fiber and an end cap coupled to the optical fiber. 
     
     
         34 . The method of  claim 33 , wherein (i) the end cap comprises a first material, and (ii) the optical fiber comprises a second material different from the first material. 
     
     
         35 . The method of  claim 34 , wherein (i) the first material comprises sapphire, and (ii) the second material comprises glass. 
     
     
         36 . The method of  claim 25 , wherein the partially reflective component comprises an end cap coupled to the optical fiber, the end cap having a coating on a surface thereof. 
     
     
         37 . The method of  claim 36 , wherein the coating has a reflectivity to at least one wavelength of the multi-wavelength output beam ranging from approximately 1% to approximately 10%. 
     
     
         38 . The method of  claim 36 , wherein the coating comprises one or more metallic layers. 
     
     
         39 . The method of  claim 36 , wherein the coating comprises one or more dielectric layers. 
     
     
         40 . The method of  claim 25 , wherein the partially reflective component comprises a void disposed within the optical fiber. 
     
     
         41 . The method of  claim 40 , wherein the void comprises therewithin air or vacuum. 
     
     
         42 . The method of  claim 25 , wherein (i) the optical fiber comprises first and second optical fiber portions coupled together at an interface, and (ii) the partially reflective component comprises the interface. 
     
     
         43 . The method of  claim 42 , wherein (i) the first optical fiber portion comprises a core region optically upstream of the partially reflective component, (ii) the second optical fiber portion comprises a core region optically downstream of the partially reflective component, and (iii) a diameter of the core region of the second optical fiber portion is larger than a diameter of the core region of the first optical fiber portion. 
     
     
         44 . The method of  claim 42 , further comprising an adapter for in-coupling light from the first optical fiber portion into the second optical fiber portion. 
     
     
         45 . The method of  claim 44 , wherein the adapter comprises a fiber taper or a mode field adapter.