Dwivedi Ranjeet, Kumar Arun
Appl Opt. 2017 Jun 1;56(16):4685-4689. doi: 10.1364/AO.56.004685.
We propose a highly sensitive temperature sensor based on modal interference in a metal-under-clad ridge waveguide (MUCRW) with polydimethylsiloxane as the upper cladding. The proposed sensor exploits the interference between the fundamental and the first higher order TE modes of the MUCRW. The increased fractional modal power in the ambient medium due to the metal under-cladding along with the high thermo-optic coefficient of the upper cladding results in a very significant change in the modal characteristics of the two interfering modes with temperature variation. Moreover, the effect of temperature change is more pronounced for the higher order mode compared with the fundamental mode, resulting in an ultrahigh sensitivity of the modal interference to the ambient temperature. The sensitivity of the proposed sensor structure is found to be as high as 8.35 nm/°C, which, to the best of our knowledge, is the highest reported sensitivity in any integrated optic waveguide-based temperature sensor.
我们提出了一种基于模态干涉的高灵敏度温度传感器，该传感器采用以聚二甲基硅氧烷作为上包层的包层下金属脊形波导（MUCRW）。所提出的传感器利用了MUCRW的基模和一阶高阶TE模之间的干涉。由于包层下金属以及上包层的高热光系数，环境介质中分数模态功率的增加导致两个干涉模的模态特性随温度变化发生非常显著的变化。此外，与基模相比，高阶模的温度变化效应更为明显，从而导致模态干涉对环境温度具有超高灵敏度。所提出的传感器结构的灵敏度高达8.35 nm/°C，据我们所知，这是任何基于集成光波导的温度传感器中报道的最高灵敏度。
