$C$-Band Optical 90$^{\circ}$-Hybrids Based on Silicon-on-Insulator 4 $\times$ 4 Waveguide Couplers

Abstract

We demonstrate 4times4 multimode interference couplers in a silicon-on-insulator rib waveguide technology that enable compact integrated fully passive optical 90deg-hybrid devices with operation across the <i xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">C</i> -band.