Compact and high efficiency polymer air-trench waveguide bends and splitters

Abstract

A fabrication process for PFCB waveguide air-trench bends with scanning electron microscope (SEM)-based electron beam lithography (EBL) and autoalignment has been developed and high efficiency air-trench bends (97.2% for TE polarization and 96.2% for TM polarization) have been demonstrated. We have successfully developed a high aspect ratio (18:1) anisotropic PFCB etch using a CO/O 2 etch chemistry in an inductively coupled plasma reactive ion etcher (ICP RIE) for PFCB waveguide air-trench splitter fabrication. The fabricated splitters show a 90.1% overall efficiency and ~ 85-to-15 (85:15) splitting ratio for 950 nm wide splitter trench, which closely matches 2D-FDTD simulation results. Using air-trench bends, an ultracompact PFCB arrayed waveguide grating (AWG) 8 x 8 wavelength demultiplexer for Wavelength Division Multiplexing (WDM) application had been designed. Compared to a conventional AWG in the same material system, the air-trench bend AWG reduces the area required by a factor of 20. Compact ring resonators using these splitters and bends has been designed and fabrication and improvements are currently underway.