Passive active resonant coupler (PARC) platform with mode expander

Summary form only given.There is a need for integrating various active and passive devices on a single substrate to increase the functionality of optical modules. In our previous work, we had proposed and demonstrated a platform technology for this purpose called the passive active resonant coupler (PARC). We have integrated a mode expander to the PARC platform by incorporating three waveguides in the vertical direction. The top waveguide is the active waveguide (AW) optimized for gain at 1.55 /spl mu/m. The middle waveguide is a confined passive waveguide (CPW) optimized for passive devices like splitters etc. The bottom waveguide is a large loosely confined passive waveguide ILPW) optimized for high coupling efficiency to a cleaved standard single-mode fiber. The mode is coupled between respective waveguides using resonant coupling over a taper.