Excelitas’ C30659 Series includes a Si or InGaAs Avalanche Photodiode (APD) with a hybrid preamplifier, in the same hermetically-sealed TO-8 package, to allow for ultra low noise operation.
The Si APDs used in these devices are the same as used in Excelitas’ C30817EH, C30902EH, C30954EH and C30956EH products, while the InGaAs APDs are used in the C30645EH and C30662EH products. These detectors provide very good response between 830 and 1550 nm and very fast rise- and fall-times at all wavelengths. The preamplifier section of the module uses a very low noise GaAs FET front end designed to operate at higher transimpedance than Excelitas’ regular C30950 Series.
The C30659 is pin-to-pin compatible with the C30950 Series with a negative output. An emitter follower is used as an output buffer stage. To obtain the wideband characteristics, the output of these devices should be capacitively- or AC-coupled to a 50 Ω termination. The module must not be DC-coupled to loads of less than 2,000 Ohms. For field use, it is recommended that a temperature-compensated HV supply be employed to maintain a constant responsivity over temperature.