Parallel end-butt coupling for optical integrated circuits

Abstract

The method of parallel end-butt coupling has been used to couple GaAs laser diodes to Ta 2O5 thin film waveguides. Theoretical caluclations predict that a coupling efficiency into the lowest order waveguide mode of 90% is achievable if the thicknesses of the waveguide (tg) and the laser light emitting layer (tL) are equal. Experimentally, efficiencies as high as 45.1% have been measured for laser and waveguide combinations with t/tL = 0.34. The tolerance to misalignment of the laser and waveguide has been theoretically and experimentally evaluated.