Polarization combiner/splitter

A method for making an polarization combiner/splitter comprising the steps of:

• providing a first GRIN fiber;
• providing a first polarization mode maintaining fiber;
• splicing the first GRIN fiber to the first polarization mode maintaining fiber, thereby forming a first optical assembly;
• forming a first GRIN lens;
• providing a second GRIN fiber;
• providing a second polarization mode maintaining fiber;
• splicing the second GRIN fiber to the second polarization mode maintaining fiber, thereby forming a second optical assembly;
• forming a second GRIN lens;
• providing a first fiber alignment structure, wherein the first fiber alignment structure includes two holes;
• inserting the first optical assembly into one of the two holes in the first fiber alignment structure;
• inserting the second optical assembly into the other hole of the first fiber alignment structure;
• orienting the first and second optical assemblies so that the polarization modes maintained by the first and second polarization mode maintaining fibers are orthogonal to one another;
• coupling the first and second optical assemblies to the first fiber alignment structure;
• providing a third GRIN fiber;
• providing a single mode optical waveguide fiber;
• inserting the third optical assembly into the single fiber alignment structure;
• coupling the third optical assembly to the single fiber alignment structure, thereby forming a second fiber alignment structure assembly;
• providing a walk-off crystal;
• aligning the optical axes of the first and third optical assemblies with one another, wherein the first and second fiber alignment structure assemblies are spaced apart one from another;
• positioning the walk-off crystal between the first and second fiber alignment structure assemblies;
• orienting the walk-off crystal so that light emitted from the first optical assembly passes through the walk-off crystal without changing direction and so that light emitted from the second optical assembly is directed into the third optical assembly;
• and
• fixing the position of the first fiber alignment structure assembly, the walk-off crystal and the second fiber alignment structure assembly with respect to one another.