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A highly sensitive waveguide temperature sensor based on asymmetric Mach–Zehnder interferometer was designed and experimentally demonstrated. The interferometer is based on the polymer/silica hybrid waveguide structure, and Norland Optical Adhesive 73 (NOA 73) was employed as the waveguide core to enhance the temperature sensitivity. The influence of the different length differences between the two interferometer arms on the sensitivity of the sensor was systemically studied. It is shown that the maximum temperature sensitivity of −431 pm °C−1 can be obtained in the range of 25 °C−75 °C, while the length difference is 92 μm. Moreover, the temperature sensitivity contributions from different core materials were also investigated experimentally. It is shown that the waveguide material and microstructure of the device have significant influences on the sensitivity of the waveguide temperature sensor. [ABSTRACT FROM AUTHOR]

Optical loss induced by the arbitrary structure discontinuity in the Au stripe that supports long-range surface plasmon-polaritons (LRSPPs) propagation is investigated in this paper. A broad range of arbitrary gap sizes, 4 to 20 μm, is reported for 25 nm thick Au stripe with different widths embedded in 5 μm thick optically symmetric polymer SU-8. The simulations and experimental data find a high tunneling efficiency of the long-range mode power transmission of larger than 50% over a 10 μm gap at a wavelength of 1550 nm. Accordingly, a thermally activated in-line Mach–Zehnder interferometer switch based on the guiding of LRSPPs along Au stripe with gaps is designed and fabricated. Switching characteristics are analyzed upon heating one arm of the interferometer through the passage of current therein. The fabricated switch exhibits an extinction ratio of 17 dB with a driving power of 13 mW. The results prove that LRSPPs are insensitive to technological imperfections and waveguide interruptions, which is of benefit to active plasmonic device applications. [ABSTRACT FROM AUTHOR]

The inductively coupled plasma etching parameters for fabricating sensing windows of integrated Mach-Zehnder interferometer sensor based on polymers are systematically investigated. Under the optimum etching condition, we fabricate an improved sensing waveguide with three sensing surfaces, whose sensitivity can be enhanced by a factor of 3.5 in theory. Through precisely controlling the etching time, low propagation loss and high hydrophilicity are both achieved in the etched sensing waveguide. This optimizing approach along with rapid response and stable operation has rendered the MZ1 wave-guide sensor more competent to practical requirements of R1 sensing and biochemical sensing. [ABSTRACT FROM AUTHOR]