Laplatine Loic, Messaoudene Sonia, Gaignebet Nicolas, Herrier Cyril, Livache Thierry
Univ. Grenoble Alpes, CEA, LETI, 38054 Grenoble, France.
Aryballe, 38000 Grenoble, France.
Sensors (Basel). 2024 Mar 6;24(5):1712. doi: 10.3390/s24051712.
Silicon photonic sensors based on Mach Zehnder Interferometers (MZIs) have applications spanning from biological and olfactory sensors to temperature and ultrasound sensors. Although a coherent detection scheme can solve the issues of sensitivity fading and ambiguity in phase direction, the measured phase remains 2π periodic. This implies that the acquisition frequency should ensure a phase shift lower than π between each measurement point to prevent 2π phase jumps. Here, we describe and experimentally characterize two methods based on reference MZIs with lower sensitivities to alleviate this drawback. These solutions improve the measurement robustness and allow the lowering of the acquisition frequency. The first method is based on the phase derivative sign comparison. When a discrepancy is detected, the reference MZI is used to choose whether 2π should be added or removed from the nominal MZI. It can correct 2π phase jumps regardless of the sensitivity ratio, so that a single reference MZI can be used to correct multiple nominal MZIs. This first method relaxes the acquisition frequency requirement by a factor of almost two. However, it cannot correct phase jumps of 4π, 6π or higher between two measurement points. The second method is based on the comparison between the measured phase from the nominal MZI and the phase expected from the reference MZI. It can correct multiple 2π phase jumps but requires at least one reference MZI per biofunctionalization. It will also constrain the corrected phase to lie in a limited interval of [-π, +π] around the expected value, and might fail to correct phase shifts above a few tens of radians depending on the disparity of the nominal sensors responses. Nonetheless, for phase shift lower than typically 20 radians, this method allows the lowering of the acquisition frequency almost arbitrarily.
基于马赫曾德尔干涉仪（MZIs）的硅光子传感器的应用范围涵盖从生物和嗅觉传感器到温度和超声传感器。尽管相干检测方案可以解决灵敏度衰减和相位方向模糊性的问题，但测量的相位仍然是2π周期性的。这意味着采集频率应确保每个测量点之间的相移低于π，以防止2π相位跳变。在这里，我们描述并通过实验表征了两种基于灵敏度较低的参考MZIs的方法，以减轻这一缺点。这些解决方案提高了测量的稳健性，并允许降低采集频率。第一种方法基于相位导数符号比较。当检测到差异时，参考MZI用于选择是应在标称MZI中加上还是减去2π。它可以校正2π相位跳变，而不管灵敏度比如何，因此单个参考MZI可用于校正多个标称MZI。第一种方法将采集频率要求放宽了近两倍。然而，它无法校正两个测量点之间4π、6π或更高的相位跳变。第二种方法基于标称MZI测量的相位与参考MZI预期相位之间的比较。它可以校正多个2π相位跳变，但每个生物功能化至少需要一个参考MZI。它还将校正后的相位限制在期望值周围[-π, +π]的有限区间内，并且根据标称传感器响应的差异，可能无法校正几十弧度以上的相移。尽管如此，对于通常低于20弧度的相移，这种方法几乎可以任意降低采集频率。
