Grant: Idea to Innovation

Optical sensors - such as those based on fibre Bragg gratings - are gaining commercial importance due to attributes such as immunity from electromagnetic interference, small size and weight, chemical resistance, and ability to operate at extreme temperatures. They play a key role in a number of important industrial sectors, including oil and gas (for down-hole sensing and within refineries), pipeline monitoring, aerospace technology (structural monitoring of aircraft), and civil engineering (structural monitoring of bridges and buildings).Most optical sensors operate on the principle of detecting a shift in wavelength of the light reflected or transmitted by the sensor, where the shift is caused by a change in some target measurand (temperature, pressure, strain, etc.). Often, there is a need to detect exceedingly minute wavelength shifts on the order of 1 trillionth of a meter. Conventional systems used for this purpose are typically based on diffraction gratings or tunable lasers, and are relatively large, delicate, and costly scientific instruments. Alternative instruments that are smaller, more robust, and less expensive, are needed to enable expanded applications of optical sensors.The proposed work springs from our recent development of a new type of on-chip spectrometer. In place of a diffraction grating, this spectrometer employs sub-millimeter scale optical waveguides as a dispersive element to resolve the wavelength spectrum of a light signal. In proof-of-principle work, we have already demonstrated the ability to detect wavelength shifts from fiber Bragg grating sensors, with performance comparable to that achieved using a bench-top commercial instrument.Building on this, we propose to develop a fully integrated system capable of simultaneously detecting wavelength shifts from multiple sensors distributed on multiple optical fibers. This instrument will be smaller than a typical smart phone, and will have performance that exceeds that of most large-scale commercial instruments. This work promises to enhance Canada's leadership position in fibre-based optical sensing technologies.