A mounting method on configuring a wavelength-voltage relation of an optical tunable bandpass filter (TBF) for actuation & control

Abstract

Although commercial tunable optical filters with integrated electronic controls are available, it costs much more than a manually tunable filter. This paper aims to demonstrate a simple procedure on mounting a manually tunable bandpass filter (TBF), with a mathematical model to represent the relation between the sensor's output and the central wavelength of the filter. A position sensor is used to match the central wavelength of the filter and the sensor's output. This results in a simple mount to actuate the TBF and the position of the wavelength is simply translated in terms of the output voltage. Although the accuracy of the system is not commercial grade, a rudimentary setup with promising results can be observed. We present the mount using very simple components, utilizing motorized actuation, with an analog voltage output which can bear any desired resolution for digitization. Finally, a mathematical model is developed to represent the wavelength-voltage relation. This setup paves way for researchers to log the central wavelength from tunable filters without the need for any equipment, at a much lower cost compared to its commercial counterparts.