Passive Network of Fabry-Perot based Sensors with Wavelength Multiplexing Capabilities

We introduce a technology for robust and low maintenance sensor networks capable of detecting micro-g accelerations in a wide frequency bandwidth (above 1,000 Hz). Sensor networks with such performance are critical for navigation, seismology, acoustic sensing, and for the health monitoring of civil structures. The approach is based on the fabrication of an array of highly sensitive accelerometers, each using a Fabry-Perot cavity with transparent passbands at specific wavelengths that allows for embedded optical detection and serialization. A unique feature of this approach is that no local power source is required for each individual sensor. Instead one global light source is used, providing an optical input signal which propagates through an optical fiber network from sensor to sensor. The information from each sensor is embedded into the transmitted light as a wavelength division multiplexed signal. We present for the first time the preliminary demonstration of a system of two linear serialized wavelength division multiplexed Fabry-Perot sensors with the potential for a less then 1.5dB through signal loss per device. The sensors are formed using an optical thin film multilayer structure that takes advantage of the natural non-uniformity in deposited thin films to allow serialization.