Monolithic Integration of a Semiconductor Optical Amplifier and a High-Speed Photodiode With Low Polarization Dependence Loss

We demonstrate the monolithic integration of a buried heterostructure semiconductor optical amplifier (SOA) and a deep ridge PIN photodiode for high-speed on-off keying links at 1.55 μm. The structure allows separate optimization of the SOA and the photodiode. The integrated receiver presents simultaneously a peak responsivity of 88 A/W with a low polarization dependence loss (<; 1 dB), a low noise figure (8.5 dB), and a wide 3-dB electrical bandwidth (≈ 50 GHz). This corresponds to a very large gain-bandwidth product of 3.5 THz. To our knowledge, this is the first time that a monolithically integrated SOA-PIN receiver has achieved such performances.