Double-Stage Taper for Coupling Between SOI Waveguides and Single-Mode Fiber

Abstract

<para xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> A low-loss polarization-independent and wavelength-insensitive mode converter is demonstrated for coupling between standard single-mode fiber (SMF) and 1.5-<formula formulatype="inline"><tex>$\mu$</tex></formula>m-thick silicon waveguides. This mode converter consists of a double-stage taper fabricated using planar processing. Optical testing results show facet loss of approximately <emphasis><formula formulatype="inline"><tex>$-$</tex></formula></emphasis>1.5 dB/facet, for TE and TM polarizations across a wide wavelength range. </para>