This device can be used either as a polarization beam combiner to combine light beams from two PM input fibers into a single output fiber, or as a polarization beam splitter to split light from an input fiber into its two orthogonal polarization components. An important application of this device is polarization division multiplexing or demultiplexing in optical systems to increase their transmission capacity. In addition, as a pump combiner in optical amplifiers, the device efficiently combines the output from two pump lasers into a single fiber to increase the optical amplifier’s saturation power and to reduce its polarization sensitivity. The wide operation bandwidth and high power handling capability make the device very attractive for next-generation amplifier systems. Finally, with a rugged stainless steel package designed for high optical performance and stability, this compact device offers low excess insertion loss, low back reflection, and high extinction ratio that equal or surpass others on the market.