Measurements of InGaAs metal-semiconductor-metal photodetector nonlinearities

摘要

The use of 200-mW low-noise lasers in externally modulated fiber-optic links can increase the link dynamic range and reduce the noise figure by 10 dB per current decade above 1 mA. To realize this, these systems require high-speed photodetectors (PDs) capable of detecting up to 50 mA. To data, PDs capable of detecting this current level have been limited to frequencies below a few Gigahertz~1, although 5-10 mA commercial 15-18 GHz devices are now available. Metal-semiconductor-metal (MSM) PDs offer possible optical power density and heat dissipation advantages over commercial p-i-n structures because the incident light can be spread over a larger surface area. These devices however, may be limited by space-charge effects~(2-4) due to their less uniform absorbing region electric field. Here we present experimental nonlinearity (NL) results showing that these devices behave similarly to p-i-n devices when illuminated with high powers.