For the entire system, however, the amplifier noise is the dominant source of noise. To reduce the overall noise of the detector/amplifier module, the capacitance connected to the amplifier has to be as small as possible. This is achieved by making the connec¬tions as short as possible. With its H0 series, LASER COMPONENTS has developed an APD receiver, with an inherent noise of nearly zero.
Depending on the integrated feedback resistor, a bandwidth from DC up to 80MHz can be achieved. If the SAR500, a Si APD with a diameter of 500μm, is integrated, the module has a noise equivalent power (NEP) of only 4.86fW/√(Hz) at an amp¬lification of 3 x 107V/W. With the 80μm or 200μm InGaAs APD of the IAG series, the following values can be achieved: 1.1 x 106V/W @ 0.47pW/√(Hz).
Due to the very compact, modified TO-5 housing with a diameter of approximately 5 mm, the H0 series APD receivers can be integrated into small systems with which, for example, distances can be measured or the smallest light signals detected.