Abstract

Silicon photonics is a rapidly advancing technology [1]. Silicon based slot-waveguides for high optical mode confinement of quasi-TE (vertical slot) and quasi-TM (horizontal slot) mode have been demonstrated independently [2,3]. These structures are highly birefringent, which limits their usability in photonic devices. We propose a non-birefringent structure based on slot waveguides. To present the idea, a symmetric cross-slot waveguide with horizontal and vertical slots with widths, w_sh=w_sv=60 nm, in a silicon dioxide environment (n_SiO2=l.46) is shown in Fig. la. The material of the rail is amorphous silicon (n_a-Si=3.58) with height, w_h=300 nm, and width, w_r=120 nm. Also shown is the intensity distribution of the quasi-TE mode in the structure, simulated with the Film Mode Matching (FMM) method [4]. As expected, the quasi-TM mode has the same effective index as the TE mode and its mode field is confined into the horizontal slot.

© 2009 IEEE