An optical notch filter has been designed based on a silicon-slab Photonic Crystal (PhC) W1 waveguide. Birefringence originated usual performance degradation of notch filters has been eliminated by optimizing the slab-thickness and radius of the holes to embed a TE pass filter in the same structure. This resulted in TE and TM transmittances as $\approx$ $\mathrm{-1.5}$ dB and $\approx$ $\mathrm{-28}$ dB respectively at the wavelength $\mathrm{1550}$ nm. Structural parameters of the device are represented by normalizing them with respect to the lattice constant such that the structure can be scaled based on the application wavelength. Thereafter, generation of the mini stop band (MSB), i.e. notch-band, has been studied for various relative longitudinal-shifts of the lateral cladding for different filling fractions. Two different longitudinal-shifts are combined in a footprint of $\mathrm{9.8 \times 7.35}$ ${\mu \rm {m}^{2}}$ to realize a $\mathrm{10}$ nm notch-band having a notch suppression of $\approx$ $\mathrm{27}$ dB. Application of the notch-filter as a refractive index sensor has been investigated that exhibits its sensitivity as $\mathrm{500}$ nm/RIU. The potentiality of the device in applications like - bio-sensing (e.g., detection of morphological forms of certain bacteria, and some typical viral particles) and industrial measurements (typically, sensing of Ethyl Alcohol percentage in aqueous solution) has also been explored.

中文翻译：

---

具有 TM 抑制和传感应用同时能力的紧凑型 TE 陷波滤波器

基于硅板光子晶体 (PhC) W1 波导设计了光学陷波滤波器。通过优化孔的板厚和半径以在同一结构中嵌入 TE 通滤波器，消除了由双折射引起的陷波滤波器的通常性能下降。这导致 TE 和 TM 透射率为$\大约$ $\mathrm{-1.5}$ 分贝和 $\大约$ $\mathrm{-28}$ dB 分别在波长 $\mathrm{1550}$纳米。器件的结构参数通过相对于晶格常数对它们进行归一化来表示，这样结构就可以根据应用波长进行缩放。此后，针对不同填充率的横向包层的各种相对纵向位移，研究了微型阻带 (MSB)，即陷波带的产生。两个不同的纵向位移组合在一个足迹中$\mathrm{9.8 \times 7.35}$ ${\mu \rm {m}^{2}}$ 实现一个 $\mathrm{10}$ nm 陷波带，陷波抑制为 $\大约$ $\mathrm{27}$D b。已经研究了陷波滤波器作为折射率传感器的应用，其灵敏度为$\mathrm{500}$纳米/RIU。还探索了该设备在诸如生物传感（例如，检测某些细菌的形态形式和一些典型的病毒颗粒）和工业测量（通常是检测水溶液中的乙醇百分比）等应用中的潜力。