New low-noise APD receivers

LASER COMPONENTS presents its new avalanche photodiodes receivers: The H0 series. Supplied in a very compact, modified TO5 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.

The simplest way to use a detector is with an integrated receiver circuit. Here the quality is judged according to the amount of noise produced.

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 connections 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 80 MHz can be achieved. If the SAR500, a Si APD with a diameter of 500 μm, is integrated, the module has a noise equivalent power (NEP) of only 4.86 fW/sqrt(Hz) at an amplification of 3 x 107 V/W. With the 80 μm or 200 μm InGaAs APD of the IAG series, the following values can be achieved: 1.1 x 106 V/W @ pW/sqrt(Hz).

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