Measurements of InGaAs metal-semiconductor-metal photodetector nonlinearities

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 MSM photodetectors (PDs) capable of detecting up to 50 mA. Here we present experimental nonlinearity (NL) results showing that these devices behave similarly to p-i-n devices when illuminated with high powers. The PD under study has an undoped InGaAs active-layer thickness of 0.5 /spl mu/m.