An Optical Control System Based on Received Intensities from an Optical Sensor

摘要

Optical fiber sensors have attained lots of attention due to its light weight, small volume, and high precision. The optical sensors can measure a variety of physical quantities, such as temperature, pressure, strain, etc. However, some optical sensor systems require wavelength measuring instrument which is difficult for precise alignment, sensitive to mechanical impact, and large volume to install. An optical sensor system is proposed, which does not require an optical wavelength analyzing instrument. The proposed system stores the intensity for each wavelength of an optical source to eliminate the wavelength analyzing instrument. The optical intensity data can be used to identify the corresponding wavelength, because each wavelength of an optical source has different intensity. In the proposed system, wavelengths incident on detectors are identified using received intensities through wavelength vs. intensity table on the control unit. The wavelength which is converted from the intensity received by the detector in our system reflects the current physical quantity state. Base on the state estimated by the wavelength, the proposed system can control the physical quantity to the desired value. The proposed system is extended to limit a physical quantity variation within a pre-determined range employing a high pass filter and a low pass filter, and monitoring the intensities on detectors in the system. An optical control algorithm for the proposed system is suggested. The proposed system is simple to align, resistant to exterior impact, and easy to maintain in real applications.