A hydrogen purity sensing system includes a light source which provides an optical signal through a fiber optic cable. A hydrogen purity sensor is provided in the system which comprises a multilayered nanostructural film of high refractive index and low refractive index materials for receiving the optical signal. The system further includes a photodetector for receiving a reflected optical signal from the hydrogen purity sensor and a processing circuitry coupled to the photodetector for analyzing the reflected optical signal.