Werquin Sam, Verstuyft Steven, Bienstman Peter
Photonics Research Group, INTEC Department, Ghent University - imec, Sint-Pietersnieuwstraat 41, 9000 Gent, Belgium.
Opt Express. 2013 Jul 15;21(14):16955-63. doi: 10.1364/OE.21.016955.
Silicon-on-insulator microring resonators have proven to be an excellent platform for label-free nanophotonic biosensors. The high index contrast of silicon-on-insulator allows for fabrication of micrometer-size sensors. However, it also limits the quality of the resonances by introducing an intrinsic mode-splitting. Backscattering of optical power at small waveguide variations lifts the degeneracy of the normal resonator modes. This severely deteriorates the quality of the output signal, which is of utmost importance to determine the performance of the microrings as a biosensor. We suggest an integrated interferometric approach to give access to the unsplit, high-quality normal modes of the microring resonator and experimentally show an improvement of the quality factor by a factor of 3.
绝缘体上硅微环谐振器已被证明是用于无标记纳米光子生物传感器的优秀平台。绝缘体上硅的高折射率对比度使得能够制造微米尺寸的传感器。然而，它也通过引入固有模式分裂来限制谐振的质量。在小的波导变化处光功率的反向散射消除了正常谐振器模式的简并性。这严重降低了输出信号的质量，而输出信号质量对于确定微环作为生物传感器的性能至关重要。我们提出一种集成干涉测量方法，以获取微环谐振器未分裂的高质量正常模式，并通过实验表明品质因数提高了3倍。
