Compact Polarization-Independent 90:10 Power Divider With Wide Bandwidth

This paper presents an ultra-compact, polarization-insensitive asymmetric (90:10) power splitter based on a modified multimode interference (MMI) structure on a silicon-on-insulator (SOI) platform. The device integrates a unique combination of rectangular and trapezoidal sections within the MMI region, achieving a remarkably small footprint of only 3.3 μm × 5 μm. Experimental results demonstrate that the splitter successfully operates over a 100-nm bandwidth (1500-1600 nm), supporting both transverse electric (TE) and transverse magnetic (TM) modes with minimal performance variation. The measured excess loss (EL) remains below 1 dB for the TE mode and below 1.8 dB for the TM mode, while maintaining the target 90:10 splitting ratio. Furthermore, the splitting ratio is highly tunable from 60:40 to 90:10 by simply adjusting the length of the rectangular section, showcasing the versatility the design. This work provides a high-performance solution for applications requiring compact and polarization-independent power splitting in densely integrated photonic circuits.