Photodiode preamplifier systems: low-noise positive-feedback
Abstract
Positive feedback circuits have been developed that allow an NEP (1.42, 500, 1) of 0.01 pW per sq root Hz or better for cooled intrinsic germanium photodiodes of up to 6-mm diam. These circuits have also been tested at room temperature with silicon photodiodes and with test capacitors; they may be used with other transducers that have a capacitance as their dominant circuit component. Circuits that had one-half-power frequencies of 2-3 Hz with no feedback have routinely achieved bandwidth enhancement factors larger than 400 without degrading the original NEP. The technique is not limited to low frequency.
- Publication:
-
Applied Optics
- Pub Date:
- February 1977
- DOI:
- 10.1364/AO.16.000385
- Bibcode:
- 1977ApOpt..16..385F
- Keywords:
-
- Feedback Amplifiers;
- Feedback Circuits;
- Low Noise;
- Photodiodes;
- Positive Feedback;
- Preamplifiers;
- Field Effect Transistors;
- Germanium;
- Signal Detection;
- Signal To Noise Ratios;
- Silicon Junctions;
- Electronics and Electrical Engineering;
- DETECTORS;
- PHOTODIODES