Laser system with doped fiber components

Abstract

A laser amplifier includes a pump source and an optically active fiber having an input portion configured to receive a signal source and an output portion. The pump source is optically coupled to the optically active fiber. The laser amplifier also includes an output fiber optically coupled to the output portion of the optically active fiber. The output fiber includes a rare-earth element. The laser amplifier further includes a beam expansion section joined to the output fiber.

What is claimed is: 
     
         1 . An optical isolator system comprising:
 an optically active input fiber;   an optical element having an input and an output, the input coupled to the optically active input fiber, wherein the optical element is characterized by an optic axis, a first transmittance in a first direction along the optic axis, and a second transmittance less than the first transmittance in a second direction opposite to the first direction; and   an output fiber coupled to the output of the optical element.   
     
     
         2 . The optical isolator system of  claim 1  wherein the output fiber comprises an optically active fiber. 
     
     
         3 . The optical isolator system of  claim 1  wherein the optically active input fiber comprises a double-clad fiber including a rare-earth doped core. 
     
     
         4 . The optical isolator system of  claim 1  wherein the optical element comprises a Faraday isolator. 
     
     
         5 . A laser source comprising:
 a seed source;   an optical circulator including a first port coupled to the seed source, a second port, and a third port;   an amplitude modulator characterized by a first side and a second side, wherein the first side is coupled to the second port of the optical circulator; and   a first fiber amplifier characterized by an input end and a reflective end, wherein the input end is coupled to the second side of the amplitude modulator, the first fiber amplifier comprising:
 an active fiber section; 
 a pump source coupled to the active fiber section by a pump coupler, wherein the pump coupler includes a rare-earth doped fiber; and 
 a second fiber amplifier coupled to the third port of the optical circulator. 
   
     
     
         6 . The laser source of  claim 5  wherein the active fiber section comprises a double clad fiber including a rare-earth dopant ion. 
     
     
         7 . The laser source of  claim 5  wherein the second fiber amplifier comprises:
 a second active fiber section; and 
 a second pump source coupled to the second active fiber section by a second pump coupler, wherein the second pump coupler includes a second rare-earth doped fiber. 
 
     
     
         8 . The laser source of  claim 5  wherein the second fiber amplifier comprises a polarization-maintaining fiber. 
     
     
         9 . The laser source of  claim 5  further comprising: a doped fiber coupled to the second fiber amplifier; and a beam expansion section joined to the doped fiber. 
     
     
         10 . The laser source of  claim 5  wherein the reflective end of the first fiber amplifier comprises a Fiber Bragg Grating (FBG). 
     
     
         11 . An optical coupler comprising:
 a first fiber including an input facet configured to receive a pump source;   a second fiber including an input facet configured to receive a signal source, wherein the second fiber includes a rare-earth dopant ion; and   a coupling section between the first fiber and the second fiber.   
     
     
         12 . The optical coupler of  claim 11  wherein the second fiber comprises a core including the rare-earth dopant ion, a first cladding surrounding the core, and at least a second cladding surrounding the first cladding. 
     
     
         13 . The optical coupler of  claim 11  wherein the rare-earth dopant ion comprises at least one of erbium or ytterbium. 
     
     
         14 . The optical coupler of  claim 11  wherein a cladding of the first fiber is fused to a cladding of the second fiber in the coupling section. 
     
     
         15 . An optical beam splitter comprising:
 an optically active input fiber, the optically active input fiber including a rare-earth dopant ion;   an optical element having an input and at least one first output and one second output, the input connected to the optically active input fiber, wherein the optical element is characterized by a first beam with a first beam power in a first direction and a second beam with a second beam power in a second direction, wherein the second direction is different from the first direction;   a first output fiber connected to the first output of the optical element; and   a second output fiber connected to the second output of the optical element.   
     
     
         16 . The optical beam splitter of  claim 15  wherein the second beam power is substantially equal to the first beam power. 
     
     
         17 . The optical beam splitter of  claim 15  wherein the rare-earth dopant ion comprises at least one of erbium or ytterbium. 
     
     
         18 . The optical beam splitter of  claim 15  wherein the optical element comprising a plurality of outputs, each output having a beam with a respective beam power and beam direction. 
     
     
         19 . An optical system comprising:
 an optical tap having an input and an output; and   an optically active fiber connected to the input of the optical tap, wherein the optically active fiber includes a rare-earth dopant ion.   
     
     
         20 . The optical system of  claim 19  wherein the rare-earth dopant ion comprises at least one of erbium or ytterbium. 
     
     
         21 . The optical system of  claim 19  further comprising a second optically active fiber connected to the output of the optical tap. 
     
     
         22 . An optical system comprising:
 an optical component including at least one of an optical modulator or an optical switching element, the optical component having an input and an output; and   an optically active fiber connected to the input of the optical component, wherein the optically active fiber includes a rare-earth dopant ion.   
     
     
         23 . The optical system of  claim 22  wherein the rare-earth dopant ion comprises at least one of erbium or ytterbium. 
     
     
         24 . The optical system of  claim 22  further comprising a second optically active fiber connected to the output of the optical component, the second optically active fiber including a rare-earth dopant ion. 
     
     
         25 . An optical system comprising:
 an optical component including at least one of wavelength-division multiplexing (WDM) element or a fiber grating, the optical component having an input and an output; and   an optically active fiber connected to the input of the optical component, wherein the optically active fiber includes a rare-earth dopant ion.   
     
     
         26 . The optical system of  claim 25  wherein the rare-earth dopant ion comprises at least one of erbium or ytterbium. 
     
     
         27 . The optical system of  claim 25  further comprising a second optically active fiber connected to the output of the optical component. 
     
     
         28 . An optical system comprising:
 a beam shaping element having an input and an output; and   an optically active fiber connected to the input of the beam shaping element, wherein the optically active fiber includes a rare-earth dopant ion.   
     
     
         29 . The optical system of  claim 28  wherein the rare-earth dopant ion comprises at least one of erbium or ytterbium. 
     
     
         30 . The optical system of  claim 28  further comprising a second optically active fiber connected to the output of the beam shaping element. 
     
     
         31 . An optical system comprising:
 a Diffractive Optical Element (DOE) having an input and an output; and   an optically active fiber connected to the input of the DOE, wherein the optically active fiber includes a rare-earth dopant ion.   
     
     
         32 . The optical system of  claim 31  wherein the rare-earth dopant ion comprises at least one of erbium or ytterbium. 
     
     
         33 . The optical system of  claim 31  further comprising a second optically active fiber connected to the output of the DOE.