HIGH RESPONSIVITY, LOW DARK CURRENT, AND HIGHLY RELIABLE OPERATION OFINGAALAS WAVE-GUIDE PHOTODIODES FOR OPTICAL HYBRID INTEGRATION

We propose an InGaAlAs waveguide p-i-n photodiode (WG-PD) with a thick symmetric double-core for surface-hybrid integration onto optical pla tforms, which can be applied to low cost optical modules for access ne tworks. The waveguide structure is designed to efficiently couple to f lat-ended single mode fibers while maintaining low-voltage (less than 2 V) operation. Crystal growth conditions and a passivation technique are also investigated for obtaining high responsivity, low dark curren t and highly reliable operation. Fiber-coupled responsivity as high as 0.95 A/W, at a 1.3-mu m wavelength, and vertical coupling tolerance a s wide as +/-2.6 mu m are demonstrated for a dispersion-shifted fiber (DSF) coupling at an operating voltage of 2 V. Dark current is as low as 300 pA at 25 degrees C and 12 nA at 100 degrees C. A temperature ac celerated aging test is performed to show the feasibility of using the WG-PD in long-term practical applications.