High-performance surface-illuminated pin photodetector array for 200Gbps receiving system

A parallel array with 8 high speed surface-illuminated pin photodetectors (PDs) is designed and fabricated. The effect of absorption layer thickness on PD responsivity and bandwidth is analyzed, and the material structure is optimized accordingly. The photodetector array, which is based on the Indium Phosphorus (InP) Platform, is manufactured by Metal-organic Chemical Vapor Deposition (MOCVD) and contact photolithography. Each detector has a photosensitive surface diameter of 20 mu m and a depletion layer thickness of 1.0 mu m. All 8 pin-PDs exhibit a uniform responsivity over 0.7A/W at 1310nm and a low dark current of below 4nA at 1V reverse bias. In addition, the 8 pin-PDs exhibit a uniform -3dB bandwidth of 20GHz. The experimental results agree well with the theoretical values. The photodetector array, which has a cost-effective and simple manufacturing process, could potentially operate at a total transmission rate beyond 200Gbps for fiber optic communication applications and can be integrated with other optoelectronic devices.