Polarization-Insensitive and Broadband Optical Power Splitter With a Tunable Power Splitting Ratio

In this paper, we propose a novel tunable power splitter based on symmetric Mach-Zehnder (MZ) structure to achieve the polarization-insensitive and broadband performance. This good performance is realized by utilizing two 3 dB broadband directional couplers and square waveguides in a conventional symmetric MZ structure. Based on thermo-optic effect, the power splitting ratio of our power splitter for the TE and TM modes can be equally controlled in a wide operating bandwidth of 63 nm. Our results show a low polarization-dependent loss of 0.001-0.089 dB over a wide wavelength range of 1541-1604 nm.