Potential materials for avalanche photodiodes operating above 10Gb/s

Avalanche photodiodes have been the preferred choice for detection of signals at the bit-rates of 2.5Gb/s and 10Gb/s in optical communication networks. Current commercial avalanche photodiodes are unable to meet the demand at higher bit-rates above 10Gb/s. A review of the gain-bandwidth products reported in InP, InAlAs and Si based avalanche photodiodes is presented. We discussed the physics of avalanche photodiodes that determine the bandwidth. The effects of avalanche region width, ionization coefficient ratio, dead space and carrier velocity are considered to understand potential strategies to increase the. The advantages of adopting materials including AlGaAs, InAs and Si as multiplication layers are presented.