Abstract

Multimode interference (MMI)-based devices have become important components within integrated optical circuits requiring N × N power splitters, Mach-Zehnder interferometers (MZI’s), and optical switches. Among them, wavelength demultiplexers or polarization splitters are using the difference of effective indices for two wavelengths or polarizations. However, as the difference of effective indices gets smaller, the device length increases, and thus, the propagation loss increases and performances are degraded. In this work, quasi-states using the four-mode interference in the MMI coupler are proposed, and so, device length is shorten to be 1/5 of general device length. Also, the polarization splitter based on a multimode interference using the birefringence of photodefinable polyimide is fabricated and measured.

© 2002 Optical Society of America