Improved Resolution of Temperature Sensor Using Fast and Slow Light in a Fiber Resonator

Abstract

A novel scheme for improving the resolution of temperature sensor using fast and slow light in a fiber resonator is proposed and demonstrated experimentally. In the measurement system, the shift of resonance wavelength produced by the temperature change can be converted into strong variations of delay time. By measuring the delay time, this sensor we proposed has high-temperature sensitivity. Different from the traditional method of tracing spectrum, the temperature detection is carried out using an oscilloscope, which results in the sensor with fast response and high resolution. Moreover, the sensitivity, resolution, and measurement range of the sensor can be easily tuned by changing the <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">${Q}$ </tex-math></inline-formula> -factor of the resonator. Using this approach, we demonstrate temperature measurements at fiber resonators with low- <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">${Q}$ </tex-math></inline-formula> and high- <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">${Q}$ </tex-math></inline-formula> , respectively, as well as a <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$3.76\times 10^{-{4}}\,\,^{\circ }\text{C}$ </tex-math></inline-formula> resolution and a 2706 ns/°C sensitivity of temperature sensing are obtained. The scheme is simple in structure and easy to implement, which is particularly suitable for detecting very small temperature changes.