High-responsivity low-dark-current InGaAlAs waveguide photodiode with a symmetric double-core for optical access networks

A symmetric InGaAlAs waveguide photodiode for low cost optical hybrid integration is designed and fabricated. High responsivity of 0.95 A/W and coupling tolerance of /spl plusmn/2.6 /spl mu/m, obtained by optimising the double core structure are demonstrated. Dark current as low as 300 pA is achieved by using surface passivation.