Elite receiver optical sub-assemblies (ROSAs) are engineered based on patented Semtech Rchip technology. Our complete line of PIN and APD ROSA products spans 1310nm nanometer (nm) to 1550nm including limiting, linear and automatic gain control (AGC) functionality. Experience unparalleled signal detection with our ROSA (Receiver Optical Sub-Assembly), a cornerstone for efficient optical datacom and telecom systems. Optical Modules are categorized into LD (Laser Diode) Modules and PD (Photo Diode) Modules. The ROSA contains a high-speed PIN photodiode and a lownoise trans-impedance amplifier in a hermetically sealed TO. Semtech PIN ROSAs operate at.