High-performance, high-reliability InP/GaInAS p-i-n photodiodes and flip-chip integrated receivers for lightwave communications

High-performance, high-reliability InP/GaInAs p-i-n photodiodes have been developed for flip-chip integration. The introduction of ultra-small, planar junctions and microlenses has lead to a high quantum efficiency of 80%, a high-speed response of 21 GHz and a wide fiber alignment tolerance of over 40 μm. The metallization structure based on an Au-Su/Pt system has been developed and its stability has been confirmed by photodiode aging at 180°C for more than 3000 h. Applicability of flip-chip p-i-n photodiodes has been demonstrated by the fabrication of p-i-n/GaAs amplifier receivers. The minimization of parasitic reactances using flip-chip integration has resulted in a sensitivity of -27.4 dBm at 2 Gb/s, nonreturn-to-zero. These results show the usefulness of flip-chip integration for developing high-performance receivers for lightwave communication systems