The integration of an optical detector with a transimpedance amplifier (TIA) is a very attractive solution for high speed fiber optical communication links. This article presents our studies of the possibility of integrating a Metal-Semiconductor-Metal (MSM) detector on the same material structure as used for commercial HEMT-MMICs. Future applications such as 10 Gb/s fiber optical links are investigated. The first generation MSM detectors were fabricated for proof-of-concept. The DC and RF responsitivity at 850 nm wavelength was measured as a function of bias-voltage. A DCresponsitivity of approximately 0.5 A/W and a bandwidth above 2 GHz was achieved for an applied voltage of 10 V. An electrical model was extracted from S-parameter and DC-measurements.