In its most common form, a cube, a beam splitter is made from two triangular glass which are glued together at their base using polyester,, or urethane-based adhesives. Beam splitters in PON networks are often made with single-mode optical fiber, by exploiting evanescent wave coupling between a pair of fibers to share the beam between them. Thorlabs' Single Mode Fiber-Based Polarization Beam Combiners (PBC) or Splitters are designed to either combine two orthogonal polarizations into a single fiber or split a single input into its orthogonal linear polarizations through two fiber outputs. Light from an input fiber is first collimated, then sent through a beam-splitting optic to divide it into two. Both 1xN and 2xN splitters can be constructed in this fashion with as many as eight or more outputs, with both low.
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