REDUCED COUPLING LOSS USING A TAPERED-RIB ADIABATIC-FOLLOWING FIBER COUPLER

We present the design and experimental demonstration of a tapered-rib adiabatic-following fiber coupler (TRAF-FiC), This device is an adapta tion of a Shani-Henry mode converter fabricated in (Al)GaAs and design ed to increase the coupling efficiency of conventional optical fibers to tightly-confined semiconductor rib waveguide devices, This approach offers the potential of significantly reducing fiber butt coupling lo sses from the typical values of 7 to 10 dB to values of <1 dB, This lo ng-standing packaging problem is one of the major impediments to the w idespread acceptance of semiconductor-based optoelectronics. Moreover, the design can be implemented with minimal increase in fabrication co mplexity since it uses only a straightforward modification to epitaxia l growth, and one additional lithography and etching step.