Low Loss and Dynamically Tunable Power Splitter Based on Circular-to-Rectangular POF Converter

A tunable power splitter based on the predefined end shape of polymer optical fiber (POF) is fabricated for an efficiently integrated optical device. We show that the reshaped end fiber from round to rectangle cross section greatly reduce the interstitial space between POFs and mold-insert's waveguide. Control of power splitting ratios is realized through varying the deflection of the input fiber toward fixed output fibers for 0:100 splitting ratios. A 5-μm resolution with 1% splitting ratio accuracy can be accomplished with greater uniform illumination efficiency. Lower excess loss of 0.7 dB and insertion loss of 3.7 dB for a 3-dB splitter is measured. The observational results obtained here are confirmed by theoretical investigation as well.