This diploma thesis describes the development and production of a compact photodiode amplifier to detect the rotation of light polarization of the detection laser beam in an optical magnetometer. We measured the sensitivity, frequency response, signal/noise ratio of the photodiode amplifier, and the output signal amplitude using measuring equipment and a program created in the LabView software environment.
To test the photodiode amplifier, we used a laser, which is also used in optical magnetometers. We also used a mirror and a linear polarizer to direct the beam to the polarization beam splitter. An optical power meter was used to measure the power of the beam, and polarization change was simulated with a Faraday modulator to test the operation of the photodiode amplifier.
Using the example of an already-available prototype photodiode amplifier, we searched for suitable components that were available, drew the circuit, made a printed circuit board, and finally assembled and tested it.
The system’s sensitivity can be easily adjusted with switches. The polarization divider also allows the photodiodes’ mode of operation to be set by switching two switches between the photo-current operation (without blocking the voltage) and the photo-conductive operation (by blocking the voltage).
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