APD modules are high-sensitivity photodetectors that integrate an APD (avalanche photodiode), a temperature-compensation bias circuit, and a current-to-voltage converter. The Excelitas Hybrid Optical APD Receiver Modules are comprised of a photodetector (PIN or APD) and a transimpedance amplifier in the same hermetically sealed package. Having both an amplifier and photodetector in the same package allows low-noise pickup from the surrounding environment and reduces. MACOM's photoreceiver product line focuses on providing solutions for Test and Measurement, Aerospace and Defense, RF-over-Fiber (RFoF) and Free Space Optics (FSO) systems. All receivers are available with Si or InGaAs APDs. The performance of an APD in a specific application is often limited by the pre-amplifier, therefore the pre-amplifier needs to be chosen and implemented with great care in. The Models 7511B and 7510 are high gain low noise APD-preamp optical receivers. The compact construction (modified TO-8 header) and PCB mounting capability make them ideal for miniature applications.