Integrated Optical High-Voltage Sensor Based On a Polymeric Digital Optical Switch

Abstract

The integrated optical high-voltage sensors are useful for remote fiber-optic monitoring of high voltages under the dangerous high-voltage environments including poner distribution systems, without electromagnetic interference. They have been mainly implemented utilizing lithium niobate guided-wave diveces such as Mach-Zehnder interferometric modulators, cutoff modulators [1]. However, the modulator type voltage sensors with a single output port are inevitably affected by the changes in the light source power. In this paper, we report a high-voltage sensor utixzing a polymeric Y-branch digital optical switch [2] in an electro-optic polymer. The measurement of ac high voltages is accomplished by using the linear transfer characteristics of the digital optical switch. The logarithmic ratio of optical powers of two output ports may be also used to remove the noise caused by the power fluctuations of a light source, since the logarithmic ratio is independent of the light source power and linearly proportional to applied voltages around the operating bias point. The passive polymeric high-voltage sensor requires no electrical dc biases and no voltage dividers. It is also wavelength insensitive and fabrication-tolerant since it uses the mode evolution effect instead of interference Moreover, the sensing voltage range can be easily extended by controlling the process parameters of polymeric waveguides such as poling voltage, photobleaching time, and polymer layers thickness.